B.M.
I will second that LEAP is a wonderful program, however, it is very difficult to get into. You should contact the AIU3 to get your child enrolled in the DART program. It is a program based on the LEAP program. My son went for 3 years before entering Kindergarten, and had a great experience. They are placed in a classroom with typical peers. When my son started he was completely non-verbal, and severe. When he "graduated" the program He was speaking in sentences.
http://www.aiu3.net/ is the website for the AIU. Feel free to contact me if I can help further. I have 3 children on the autism spectrum.