If you go to the discussion forum under Bylaw etc you will find a thread with sample bylaw sites online. Be sure to set the day to 45 days to get all discussions.
As far as getting old budgets etc you may have to face the fact that you just aren't going to get much. Try asking for the "old" treasurer to meet with the "new" and bring two years banks statements and cancelled checks. This will give you a starting point since you will be able to see who checks were written to.
I know sometimes it is hard not to be irritated with people who aren't organized and haven't kept records, but if these people have been doing it for 5 years they have probably put a lot of time and effort into the school. Try going after things with a pat on the back for all their "dedication" instead of "demanding" records.
