The test is offered 3 times a year. For the 2006 testing year, it's offered June 11, October 29, and Feb. 4, 2007. Since you're at such an advanced level I'm not sure how much it would help you, but Heisig's Remembering the Kanji, Volumes 1 and 3 are great for remembering how to write the characters. You could probably get through them faster than the average person. Volume 3 would get you nearly all the characters for pre 1-kyuu, and then the only (haha) issue would be learning the readings and compounds.