I'm sorry that you're struggling with this test - the GMAT can be very frustrating.
I'd like to get some more information about your mindset, study focus, and strengths and weaknesses. This is going to take you some time - you're going to need to dig deep and realize analyze what's been going on.
First, read these two articles:
http://tinyurl.com/executivereasoninghttp://tinyurl.com/2ndlevelofgmatThink about how what you've been doing does and doesn't match up with that and how you may need to change your approach accordingly. Write down (or type up) those notes.
Then, use the below to analyze your most recent MGMAT CATs (this should take you a minimum of 1 hour):
http://tinyurl.com/analyzeyourcatsBased on all of that, figure out your strengths and weaknesses as well as any ideas you have for what you think you should do. Then come back here and tell us; we'll tell you whether we agree and advise you further. (Note: do share an analysis with us, not just the raw data. Part of getting better is developing your ability to analyze your results - figure out what they mean and what you think you should do about them! You should be able to tell me what question type and content areas fall into each of your three buckets and offer some ideas for what you should start doing for bucket 2. You'll understand what that means when you read the article!)