I am also a member of IAA. Ranking requirements for IAA can be obtained from your instructor. Do ever go to the hombu dojo in Dallas, or do you work exclusively out of Fort Worth? Either way, and instructor from Dallas shows up to your dojo on Thursdays and you can inquire.
To get your first belt (rokkyu) requires a minimum of 30 hours or 3 months. Most students are ready to prepare for the test at about 3 months of trainings (at least 3 hours a week). The next belt (gokyu) requres another 30 hours or 3 months. The other tests require 6 months and 1 year before you get ready for shodan. Shodan takes a minimum of 4 to 4 1/2 years. I don't think that I have seen anyone get it in less than 5 with many taking 7-10 years.
Another thing, rank should not be a priority. It kind of comes along as you are improving yourself in the art and as a human-being.
Any way, good luck!