If you are severely affected, you can try the California Regional Center.
If not, try a graduate school of Clinical Psychology, such as the Wright Institute in Berkeley. There is one in Oakland too, but I can't remember the name of it. You will be assessed by a student who is under the supervision of a licensed psychologist, and it will probably take longer than a typical assessment.
Do you have health insurance? The Sutter Autism Center in Sacramento takes insurance, but the wait list will be months long.