Hi Scon,
The pencil-and-paper Diagnostic Test isn't the most accurate way to assess your skills for the Official GMAT (the number of questions, the 'order' of the questions and the ratio of the question types - among other things - do NOT match what you will face on Test Day). Have you taken any practice CATs/mocks yet? If you have not, then you can take 2 for free at
www.mba.com (and they come with some additional practice materials). That score will give us a good sense of your natural strengths and weaknesses and will help provide a basis for comparison as you continue to study. A FULL CAT takes about 3.5 hours to complete, so make sure that you've set aside enough time to take it in one sitting. Once you have those scores, you should report back here and we can come up with a study plan.
Before I can offer you the specific advice that you’re looking for, it would help if you could provide a bit more information on your timeline and your goals:
1) What is your exact Test Date?
2) When are you planning to apply to Business School?
3) What Schools are you planning to apply to?
GMAT assassins aren't born, they're made,
Rich