Hi Firelighter,
My DD (who is recently 6) was diagnosed with Aspergers just before her 5 birthday.
Firstly just to answer some of your questions, you ask if it normal for a child with AS to need 1 to 1 all of the time, well yes this can often be the case, but please dont despair............thing do get better
My DD is also obsessed with numbers she was at your sons age and still is to a certain degree, but thankfully we can now curb her interests a little.
She was also more interested in adults and older children at the age of 4, she would actually cringe when the other children came near her, now however she is starting to interact with her peer, and does enjoy there company (on her terms).
When she first started school (sept 07) she needed almost constant 1 to 1 support, however 12mths on she is starting to be alot more independent, i wont pretend that its been easy at times its could only be discribed as hellish and unfortunatley we had to change schools (to a much smaller school) last March, but she is now doing wonderfully well and more importantly she is happy.
Its fantastic that you sons pre school have taken such a direct approach with your sons difficulties however its really a developmental pead that he needs to be seen by educational pyscs cant diagnose anything, they are not medically qualified to. Personally if i was you i would seek a referal either via your GP or ask the ed psyc to refer you.
I hope this helps, there are lots of people here that have walked in your shoes, personally found the not knowing far worse than the knowing IYSWIM.