Hi rx10,
While you don't necessarily "need" to work through a copy of any of the recent main Official Guides, that book is a great source for realistic practice questions (and considering that the cost of that book is relatively low, trying to study without it would not save you much money).
About 1.5 months ago, you posted that you had scored Q46/V28 on a practice CAT/mock, but it's not clear how you have been studying since then. Before I can offer you any additional advice for your studies, it would help if you could provide a bit more information on how you've been studying and your goals:
Studies:
1) Since that first CAT, how many hours have you typically study each week?
2) What study materials have you used so far?
3) On what dates did you take EACH of your CATs/mocks and how did you score on EACH (including the Quant and Verbal Scaled Scores for EACH)?
Goals:
4) Is your overall goal score still 730+ or is it something else?
5) What are your current application plans?
GMAT assassins aren't born, they're made,
Rich