The book is called "Kaplan GMAT Premier Program, 2009." I'd imagine you can look for it on Amazon.com for example, as well as our website. Prices vary; right now I see some on Amazon on sale for less than 30 USD. You would receive 4 CATs. You could re-do these CATs, but in general that is not always the best thing to do as people often remember specific questions or answers, and then the results are less accurate. We also recommend using the GMAT Prep software for 2 additional CATs.
Good luck!
Jen Kedrowski
Kaplan Test Prep & Admissions
GMAT Teacher
MBA Admissions Consultant
National Product Team Member