Since it is its own school I think it should have its own PTO. They should be contacting those parents to start getting them together to form their own group and get it off the ground.
Could you start by identifying parents who will be moving to the new school next year and then by making sure someone from that group is represented on your board?
Starting costs are sometimes difficult for new groups, so if you could just start them with seed money at the end of the year, they'll be well on their way to a new successful pto.
Face facts--those parents are probably already not giving your group a whole lot of participation on long-term projects because they'll be moving on next year. Acknowledging them and helping them get started could pay off in a couple of years when your group is in need.
Our school district currently has only one school and one PTO. HOwever, next fall we will be opening our second school (yea!). I've been asked if PTO will raise funds for playground equipment for the new school. I don't want to commit to this because we have a hard enough time raising funds for our current school. Also, the new school will be serving a small gated community and will only have about 65 students to start. The community that our current school serves will have very little contact with the new school because of location (they are about 20 miles apart).
The superintendent said now would be a good time to start a PTO group for the new school. So my questions is - how? Should the new PTO be sponsored by the one we have or do we start it fresh on it's own?