I don't know of anyone in the New York City area but, there is a large, excellent facility in Central New York (between Albany and Syracuse) that specifically addresses the needs of children and adults with Autism and Asperger's Syndrome.It is called the
Kelberman Center for Autism...you can check out their website by Googling that name.
They have contact information if you want to ask them any questions...prehaps they can direct you to someone who can diagnose you in New York City. Or you can take a nice train or bus ride to their location, should you wish to meet one of their psychologists, that is, if you need a break from school.