There's a list of providers searchable by state here, on the OASIS at MAAP website:

http://www.aspergersyndrome.org/Local.aspx

There is no reason a child can't be HG and have PDD or AS at the same time; it's possible the teachers are each seeing part of the elephant, or that some of them are just wrong.

I would try to use a neuropsych or developmental pediatrician who has extensive experience with the high-IQ end of the autism spectrum; these kids are hard to diagnose correctly.

That website also has a good discussion forum for talking about Asperger's with experienced parents.

Best wishes--
DeeDee