We answer everything - it just might take a little while. :)
You have made some really great improvement on your official tests - from 450 to 580 is great! I know you're going for an even higher score, but I just want to say: great job so far!
What is your goal score? Do you plan to continue working on your own, or are you looking at joining a class or working with a tutor?
One thing I'm noticing from what you've written is that you have gone through a whole lot of material, but you're still not satisfied with your improvement. That makes me think that we need to take a step back and talk about HOW you're studying, not just what you're studying. Perhaps the way in which you're studying isn't as effective as it could be. (Though I will note, again, that you have made good improvement so far.)
In general, getting better at this point is probably
not going to involve going and buying more new material. The issue is more likely to be making sure that you're really getting everything you can out of the materials that you already have.
Tell me about your strengths and weaknesses. I'd like to know what you think yourself, and I'd also like you to use the below article to analyze your recent MGMAT CATs.
http://www.manhattangmat.com/blog/index ... ice-tests/After you've analyzed the CATs, come back here and share your analysis (note: I don't want to see just the data from your tests. I want you to tell me what you think the data means. It's important for you to be able to analyze the data so that you can figure out what to do about it.)
Also, tell me whether you took those practice CATs under 100% official conditions (essays, length of breaks, etc.).
Finally, tell me which things stress you out the most. When you get nervous and blank out, does that tend to happen on everything? Or only on certain things or at certain times? (eg, right when you start the test, or on the question types that are harder for you)