I would call and talk with the program coordinator (Carol Horn). She should be able to give you some straight answers as to what the best way to go about trying for admission to the GT program would be.
I can't imagine them denying a student GT services simply because their previous school did not offer them.
The minimum test score for being submitted into the pool of candidates this year was 132 on the NNAT or on any one subtest of the cogat. However, parents whose children did not meet the minimums were able to submit a referral form and have their children included in the pool of candidates for consideration.
They consider so much more than just the test scores.
Have you already selected an area to live in?
If not, consider the "base" schools as well as the elementary and middle GT center schools that are assigned when you start house hunting.
Best of Luck!