Well you're just the kind of teacher we love! My Pervasive Developmental Disorder (PDD) kid finally has a teacher who understands and the difference is amazing. I got blessed with a wonderful teacher for him this year after 2 years with a horrible one. The first is in a Special Education mixed disability class but has a daughter with autism. The latter is in an autism class. Now while this should be mixed the population is such that mine was the only one with any language at all, who could read, write and do math. I'm guessing that you're in a public school. An autism school would have them separated by current capability.
And being a public school I assume you're using ABA? My kid didn't respond to ABA at all. But did fabulous in a Miller Method school. If you don't have Miller's book try to borrow one, it's fabulous. Very academic but has more specific recomendations than anything ABA. While I know there are lots of issues to getting a Miller setup in a school that doesn't have one, you won't believe the difference, how much faster kids progress. If you have a day off some day take a drive to a Miller School (last I heard I think there were 4 in NJ) and watch what goes on.
Teaching autistic kids in my humble opinion is one of the most rewarding jobs there is, if you're willing to take the longer view rather than the immediate view. They may not seem to progress day to day but one day it all comes together. And seeing one who came to you with no language and who 4 years later is reading, writing, arithmetic, and able to express enough to make himself very clear... it's just amazing! It happened to mine and I never cease to wonder at how it happened.