Putting a 5th grader with Asperger's into "a class for bad kids" is not an *appropriate* placement. I highly recommend you find an advocate asap for your IEP meetings. Have they tried a behavior plan in your IEP? Has it helped at all? Are they following it?
If you have a doctor that specializes in autism, ask the doctor to attend your IEP meeting, or to go and observe your daughter in her classroom environment. The doctor's input may prove quite valuable.
Your daughter may be acting out because the people working with her are treating her autism as a discipline issue, and not a developmental disorder. So they're treating her like she's being bad, instead of trying to work with her and make accomodations for her needs. Threatening her (with a class for bad kids) or drawing a line in the sand is a good way to get her to dig in her heels and resist.
I'm not sure what resources are available in your area. Is there an Autism Society or a autism support group near you? Either would be a good place to start. Are you near Peoria? If so, try this:
Autism Society of Illinois
PEORIA REGIONAL CHAPTER #1009
c/o Easter Seals
507 E Armstrong Ave.
Peoria, Illinois 61615
###-###-####
Diane Parrish (ext. 2241)
Email: ____@____.com
Website: http://www.autism-society.org/chapter1009
Call/email them and see if they can recommend an agency that does advocacy. They might also be able to assist you with your son as well.
I strongly recommend you get someone on your side to accompany you at the IEP meetings. An advocate, or a lawyer. Someone who knows about IEPs, the local school district, accomodations, and Illinois law. Don't let the school strongarm you into putting your child into an inappropriate placement. Check out Wrightslaw.com. And AboutAutismLaw.com.
As far as your son goes, has he been evaluated too? Is it possible that he could also have Asperger Syndrome? Or some kind of sensory integration issues? My son has AS, and he has strong sensory issues, which make it very difficult for him to be in loud, busy environments, like a lunchroom, or a restaurant. In fact, I keep a carton of earplugs in my house, and always have several pairs on me at all times. (We tried several brands until we settled on a type that he liked and could easily use himself.) It's made a world of difference for us. Any time we end up someplace noisy, I hand my son a pair of earplugs, and he's fine. It has completely eliminated the problems we had with going out to dinner. We bought them at the local drug store. They are the foam kind that easily squish up, fit into the ear, and then expand to fill. Some drown out too much sound, and frustrated him. Some expand too quickly, making it hard for him to position it quickly enough, and some are not soft enough to easily squish, so we had to play around with a few different brands, but finally found one he really likes. (They are bright pink and yellow, and sort of shaped like a rocket ship). Best things I ever bought him.
Good luck!