I don't have months though, I need official results in the beginning of January so i scheduled the test for the 4th of December. Right now my plan is to concentrate my practice efforts on quant and maybe go through the CR bible since I struggle with very hard CR questions.
Anyway anthing above 650 is fine even if right now I'm targeting a score in the 700-710 range.
You have 3 weeks , so i would suggest that you go over the MGMAT guides
once ( a guide a day should be a good pace). Attempt the accompanying questions and concentrate on the last 1/3 PS and DS questions on the OG. You can always buy the MGMAT advanced quant
for strategies for the 700+ questions, but i feel that the OG13 and the MGMAT Sets are the best source for 650 level problems along with the questions given in this forum.
If you are looking for 700-800 level questions, Legenddady has a collection that is well legendary
, and includes questions from MGMAT and GMAT PREP (exclusivly 700-800). I would give myself 1.5 weeks for review and 1.5 weeks for attempting questions.
I am quite sure, that with 3 solid weeks of practice you can score 700+...
Best of Luck!!
"When you want to succeed as bad as you want to breathe, then you’ll be successful.” - Eric Thomas