You should meet with a career counselor (They usually have them specifically for people with disabilities); They do here in Newfoundland and have helped me a lot.
As to possible careers, I'd suggest data entry. That's more or less what I've done at work and seems to fit well with the Autism psyche. Whatever you do, good luck.
I've seen several Disability Employment Advisers at the Job Centre, and most of them are worse than useless IMO, they don't even know their own rules on working hours etc for a start, one told me I could work as much as I like with no sanctions, one told me the limit was 10 hours a week, another told me the limit was £120 a week or 16 hours at minimum wage. whichever was the lesser.