John Hopkins CTY uses Thinkwell and you can go straight to Thinkwell

http://www.thinkwell.com/

and a lot cheaper. If she gets concept, all she needs to do is some exercises and move on. She may finish > 2 grades level in a year.

If she wants just practice exercises, Mathopolis is free and fun.

http://www.mathopolis.com/questions/course.php
http://www.mathopolis.com/