Polly, if the district can't find an appropriate setting to place your son in then I believe they are legally responsible for creating and funding one. A personal friend of mine forced the district (took an attorney) to create a multiple handicapped classroom for their son because there wasn't one anywhere in the area. That first year he was the only pupil but afterwards other districts started busing in their kids.
In regards to Autism training, I'll mention what happened in our district some years back that my kid and many others are benefitting from: one mother worked cooperatively with the district to develop a staff Autism training program as part of the district-wide professional development. On institute days they have brought in speakers to address the entire staff in overview fashion and in summer offer more specific training to teachers and aides who have Autism Spectrum Disorders (ASD) kids scheduled for their classrooms the following year. Booklets have been developed for this year's teacher to fill out on the student and pass on to the next covering basic problem spots that many Autism Spectrum Disorders (ASD) kids have. It's been overwhelmingly positive for students, parents, and teachers alike. Usually it's the small stuff that hangs these kids up and builds and hearing that from a professional instead of a parent makes a world of difference.