Does your GD actually have a private Asperger's diagnosis? If so, she should qualify for the IEP under the category of autism. In some districts, this may give access to a different set of services. A school psych is really not qualified to give a medical diagnosis, so if you don't have one already, I'd seek one from a developmental pediatrician, an autism center, or from a neuropsychologist who has experience with autism spectrum disorders.
Since anxiety is a problem, and normal discipline methods don't work, have they done a functional behavior analysis? If not, I'd request one, in writing. They need to take data on exactly what triggers cause problems, and what the problems are, and then they should write a behavior plan that includes both direct teaching to help these triggers not be a problem any more, and strategies that everyone at the school will follow to minimize problems from those triggers.
Our school does not write gifted matter into the IEP, but it's a factor when they discuss classroom placement.
Best wishes,
Dee
