The best people to talk to are the people that evaluated your son, and the school he will be attending. They should give you as much information you need in regards to what to do next.
You need to get your name on the Autism Waiver list, that will open up many doors for you. You can also apply for social security/disability that will help you with your son. It is important to do this early as it takes a looooooong time for your name to get to the top of the list (first come, first serve basis).
http://www.angelfire.com/tx5/autismlist/financialassistan...
http://www.autismspeaks.org/community/fsdb/category.php?s...
http://www.autismlink.com/
http://facesforkids.org/
http://www.autismsupportnetwork.com/
http://www.cindysautisticsupport.com/
I hope these sites help a little. There are so many books out there that are a good read if you like reading. Raising a Sensory Smart Child, and Eating for autism are among the many good ones out there.
Ask questions, meet with people in the Autism Circles, and hear what their experiences are. Your Early Childhood Intervention/Infant toddler services should also be able to help or answer some questions you might have.
God Bless. You are a wonderful mommy who loves her boy very much. You are truly blessed. My son was also diagnosed in June, and he too will enter the PPCD soon. Keep up the good work, PM me if you have questions. I don't know much myself but I will be happy to share my experiences with you.