It's actually best that someone who doesn't have preconceived ideas about you and your diagnosis actually do the psychological testing. If you have insurance, it can be paid for by insurance; you'll need to make some calls until you find a psychologist who does testing (not all of them do testing as part of their practice while others specialize in testing).

It seems like it is time to get that testing done objectively rather than this therapist just randomly throwing out diagnoses without testing. What you have written about your therapist doesn't inspire much confidence in her skills. A competent therapist, by this point, would probably have suggested outside testing by now because of the confusion about your diagnosis.