social group in South New Jersey?

I have an 11 year old daughter, who is cognitively impaired. She is about 4 years behind in her academics, and is lagging socially also. Alot of her social skill regression, I feel, is for lack of friends in this area to socialize with. I would love to find other parents in this area with children who might benifit from getting together. Becky is a very social child, and had a best friend her own age down the block who used to have sleepovers and play with her all the time. Recently, however, this friend has dropped her. I believe my daughters childlike ways are the reason why. This friend is growing up and is now hanging around with other older girls in the neighborhood. The situation has hurt my daughter, but she seems to be taking it fairly well. She is constantly asking about having sleepovers with the girls in her class (a special ed class). However, the girls in there are two to three years younger than her, and also do not live close by. Any sugesstions. Thanks