Being that you are a new group do you already have Bylaws? Are you a 501C non-profit? Are you independant or dependant.
These are very important questions that will dictate which way you should proceed. If you are a dependant group then the Principal may be 100% in her right to dictate how your raised funds are spent.
Now if you are an idepenant, non-profit, as I'm guessing you are, then it's going to come down to your Bylaws. If you don't have them yet then this should be a priority and you should make sure that they end up meeting your group's desires. If you already have Bylaws do they say anything regarding fundrasing, voting, quarums, etc.?
Also, what type of specialty programs are you looking at.
To sum it up though, being that this is a new school, a new Principal and I am assuming a new PTO this is the one time to set up precedence. If you "allow" your Principal to dictate exactly what your group will do and how then that's the way it will end up being, for a very long time. I agree with Tim that it's not just what the parents want, nor is it just what the Principal wants. But, the PTO should be a parent controlled and operated group (again assuming that you are an independant 501C) and as such the PTO President needs to run the group with guidance from the Principal, not just orders to be carried out.
I must say that I got very lucky this past year. We had a brand new Principal who is/was very enthusiastic, and I was just voted in as President. Over the summer last year I set up a meeting with him to let him know my priorities, things that we wanted to do, things that we have done, etc. To me this set the precedence of how the PTO was going to run in conjunction with the administration. Of course he had his own priorities, but by discussing things in this manner I was ensuring that he understood that we do our thing, with guidance from him, but also that we very much wanted to help him achieve his goals. This way everyone wins. We get to act upon the things that we want while he gets what he wants.
A good example of this was field trips. The previous Principal did not allow Field Trips ever since 9/11. The parents very much wanted field trips to come back. In this meeting I discussed this possibility, which he agreed was something he was for. First chance the group had we voted to allocate funds for each grade for field trips. He explained that he wanted to create a mobile laptop cart of up to 25 computers, but here's the difference...
If he had just come to us and said I want this, do it!, we would not have been very enthusiastic. But instead he came to us and asked for certain low cost items, such as Brittanica Online for the school, which I supported and we approved. But for the $15000 laptop cart he came to us and said that he wanted this and to obtain the funds he would chair a new fundraiser, a golf tournament. Then he requested a couple thousand dollars and for us to provide a letter to the town's school committee that we would be willing to cover the costs if we did not raise enough funds. In this way we would be able to get the laptops in December, and pay for them, with approval from the town, before the end of the school year.
The difference is that because he came to us not just with his hand out, but with a valid plan and willingness to lead it, we were willing to do these other things that we didn't have to. We didn't have to provide the $2000, but because he came to us the way he did we were more than happy to. I didn't have to provide the letter to the school committee, but because he came to us the way he did, and because he respected and supported us, I was more than willing to do so. This is mutually beneficial and has proven to be great for the school and the children.
So, I have to agree with you that you need to handle this now. You really only get this one chance to set the precedence. I would recommend a meeting with the Principal, one on one, or maybe the PTO Officers and the Principal. I would outline your priorities for the year as President. I would outline the fundraising plans and how you expect these funds to be utilized. Pretty much tell her the way it is so you can set the precedence. But at the same time you want to make her understand that you are very interested in her priorities. Ask her what she wants, where she sees need and specifics about where she wants the school to go. Obviously she wants this Library, and from what I have seen the Library is one place where town funding is very minimal. Ask her what her vision is with this new library and then maybe even offer future suggestions, such as a reading incentive program, accelerated reading program, helping to purchase the accelerated reading quizes for the school, an adopt-a-book program, book fairs and how some of the funds from these could be used for the Library, etc.
Lastly here's one last suggestion. Our Principal is very into technology, which I think is great. This year he instituted morning podcasting of the morning announcements. He actually has four kids in two teams setup the recording, running the program, etc. This goes online first thing in the am so that the parents can actually go online and hear the morning announcements each day. With this he put the school in to present at the National Computing Conference in Atlanta, Georgia. We ended up being the only school in Massachusets to be selected to attend this. The overall cost to send the four stundents and one adult each was was almost $4000. Now this was obviously not a known thing, and it was not taken into account when we created our annual budget. But once again the Principal didn't come to us and say "give me the money". If he had, even though my child and I are part of the group affected, I would not have been supportive. Instead he presented the idea and I recommended that we create a new fundraiser, or fundraisers, specifically for this goal. We provided the idea of the change jugs, like "pennies for something" and at the same time we ran our own new fundraiser in a Vendor Evening, with various vendors such as Tupperware, Mary Kay, Longerberger, and like 20 others. Each had to pay just $25 for their table and 10% of any booked parties. This ended up raising us over $3000 and allowed the PTO to fund this trip.
So the point is that as a PTO I never said, "I'd like to vote to give the Principal $4000 so he can have this". Instead I would present it as our existing funds are "off-limits", but we're willing to help by running a new fundraiser specifically focused for this purpose, as long as you're willing to help. In this way he understood that, number 1, we decide how to spend our funds (of course with his guidance) and number 2, that we are very willing to support him. It keeps the precedence that if he supports us we support him, and this is great for the school. We stay important to him, and as such he takes care of us.
So I would recommend the meeting, explain that funding this new Library is not in your existing budget, but that you are willing to present the idea to the group of running new fundraisers specifically with this long-term goal in mind.
Hope this helps and good luck,
PresidentJim