ADVICE NEEDED PLZZZZ............ 320 TO A GOAL OF 700

For quant I agree that Manhattan is very good. I think your problem would be Data Sufficiency since Problem Solving is mostly easy. Also remember that for problem solving OG is quite useless since most of the questions are very easy.

For Sentence Correction Manhattan SC is a very good book but I don't think it's the best book to start off with (unless you are getting 620+ in your diagnostic test). it can give you too much information the first time you read it and can actually unnerve you. Since you've got a 320 on your diag., I would suggest that you start off with a simpler book that gives you all the rules (something like the SC Grail) first and then go through Manhattan later once you develop a comfort level with SC.

320 to 700 is a steep jump, but I'm sure it's possible.

Good luck to you!

Check these out:
* GMAT Study Plan for GMAT Novices
* Build Your Study Plan
* Best GMAT Stories
* Best GMAT Books
* Retaking the GMAT

Good luck, manalq8!