Is this public or private? If this is public, is gifted recognized as a special education qualification in your state?
It is easy to let our emotions run rampant, and it sounds like this principal is not going to be easy to deal with. But having a good base of knowledge about your rights as a parent and about your child's rights will help you advocate more from facts instead of emotion.
If this is public school, and if your state does recognize gifted under the special education qualifications, make sure you have a letter drafted that requests your child be placed in an appropriate environment based on the recent testing and include copies of the tests. They don't have to accept outside testing, but it should be enough to require them to start their own testing process if they won't accept your results. But all that depends on the laws and requirements of your state and whether the school is public or private.
And do get the book recommended above - it's great.
