The CoGAT isn't an IQ test; you will want to contact a local professional psychologist to get testing done. The IQ test usually given at age 7 would be the WISC. It may be administered in combination with an achievement test like the WIAT.
I would recommend you look for a tester with experience in gifted kids. Testing ought to give you a good idea of giftedness. It's hard to recommend anyone specific without knowing where you are; you might look for a local gifted organization to seek a recommendation for a local tester.
