need advice - raising my math score - which kaplan book?

Kaplan2005 I believe is like a standard GMAT prep book. That is, it goes through the whole prep process - explaning what the gmat is and how your score is calculated, going through the quant basics, going through quant exercises, going through some verbal basics, going through verbal exercies and along the way, strategies (Kaplan's strategy) are included to help you nip the questions more efficiently (at least that's what Kaplan claims).

The Kaplan800, as the title suggests supposedly contains 800 level questions. I've a copy of the book. Verbal seems to be pretty tough (or maybe my verbal is crap, I don't know which is whic), but quant is a letdown. The quant questions in Kaplan800 looks like a 600+ level to me.

In my opinion, you're better off working the math questions in the math forum, or have a crack at the challenges here. But if you prefer a book, then with 3 months to go, get the Kaplan800. Since you already have the Princeton Reivew Cracking the GMAT, the Kaplan2005 would be quite unnescesary.