450 to goal of 700; Need Strategy Advice

I am scheduled to take the Gmat on May 14th 2011. I recently took my second practice exam and scored a 450. My goal is to get to a 700 or at least high 600's. I know that it is possible because I am a very dedicated and committed individual but need your advice as to what my strategy should be.

I am currently enrolled in the online manhattan gmat prep course which ends on April 2nd. From my practice two tests (my first test was a combined score of 380 and much of the improvement was from simple strategy), my verbal is much stronger than my math. I believe I just need to work harder problems for verbal because I get a majority of the 500-600 level questions correct, but get less than 50% of any level above that incorrect. I also took advantage of the GMAT Write and scored and 5 on the argument statement essay and a 4 on the issue statement essay.

Relating to the math, I really need practice in all areas because I am currently getting questions only at a 300-500 level and some 500-600. My weaker areas include Rates, FDP, VICs and inequalities. I know that I should begin doing some OG problems but am not sure where to start. I do not know if it is more efficient for me to look at certain question types at a time, or just work problems that occur one after the other in the OG guide. I know that I am capable of a high score because I had a very high undergrad GPA 3.99/4.0. My problem is that I am book smart and I have always struggled with standardized testing. I really want to good to a top B-school and know that I can accomplish my goal. Please let me know your advice regarding a good strategy to tackle OG problems as well as an overall strategy to accomplish my goal. Thank you!