I have a question about gifted testers. How do you find one?

We had our DS5 tested by a psychologist starting when he was three due to a variety of issues and it turned out he was really gifted (which we kind of knew but he was our first). We like the psychologist and she certainly helped us with behavior issues, but she is not doing anything useful for us in terms of educational support. Now that he is in Kindergarten I really need to find someone to give us guidance. The doc told us she has never had experience with kids like him. I would like to find someone new. Anybody know of someone good in the Washington, DC area? I searched on Google but nobody seems to be advertising that they are a specialist in gifted children.