There is very much hope to realise your dream in Aus.
We have 2 kids. My son (my eldest) is 9 and is on the ASD spectrum. He was diagnosed with aspergers when he was 6. He is on daily medication, and is in a mainstream school in Bexley. He has a statement that covers most of the week at school, but in reality he does not need it all the time.
I started the visa process during 2011. We were awarded our visa in April 2012 and have just completed our initial entry trip, and we hope move there by the end of July.
I did not use any agents, I felt in reality didn't bring much to the process, and found that all of them I spoke with were interested in two things, their track record and/or your wallet. My entire visa application process from my skills assessment to my medicals could not have smoother. My son's medicals were no different to any other child's medical tests.
Not all cases are the same, because my application went so well, it does not neccessary mean your's will, but hopefully it will have a happy ending to your application.
good luck
Queuball