That is a horrible story. I really feel for your daughter. but i do have some ideas!!!
1. Try taking her places to make sure that she starts to interact with other kids her age. Before you take her, prepare her. You might even want to bake some cookies for her to take so that she can start talking and playing easier, and the other kids will naturally come to her. Make sure she knows about her wheelchair, and educate her about it. That way when kids talk to her she can tell them about it so the other kids arn't as shy or afraid of her (or think she's a robot or something)
2. Buy her some really nice clothes, or toys that way she can show it off. If the kids see something that they like before they notice the wheelechair they might not be as errie about her.
3. Come with her. Be there for her for her first day. If she seems upset then tell her that she has to be strong. Remember that she can't just leave. by leaving she is letting the other kids win, and that will be horrible for the future. you cant hide her from the other kids
4. Try finding a child that is going to be going to the school that she's going to. Invite him/her over and have them play together for a while. That way she has some one to talk to and to play with when she gets to school
5. Make sure that you talk to the teacher about the childs specail needs. Make sure that she is going to protect her, but not treat her like she's different.
I hope she ends up okay, and i hope i helped