I am not an expert to advice; but can give my 2 cents..
Since you have 6 days left, do not do 1000s sets.
You did not mention what tests you have taken, whether they are
MGMAT or GMATPrep. If they are not GMATPrep, do one test. But, since you are below your target and have less time, do not do 2nd one as there are no explanaitons for GMATPrep.
39Q and 32V seems you are okay at fundamentals, but perhaps lacking at how to apply the concepts together.
First 4 days : what's your weakest area, SC,CR,RC,PS, or DS? try to practice questions in this area which have explanaitons, understand the concepts from explanations. May be you are missing how to tackle with RC. Again, do not do the ones which do not have explanations, as you will not know how to solve them and you dont have time to post here and wait for responses.
Can somebody post here which problems he needs to work on to improve from 590 to 650, whether MGMAT Qs, Kaplan Qs or anything else? I am exactly not sure what books he needs for 600-650 level
Last two days: You better review all your mistakes, fundamentals in last two days, if two days are enough to review them (you know better about your mistakes).