Are your practice scores in the range that you want to score on the real test? If not, then you will need to do more. I wouldn't try to do all of our strategy guides in just 1 month - there's a ton of material in the books. 2 months might be enough time. But you might not have to do everything - we need to see what your strengths and weaknesses are.
First, I am worried that you are following the "quantity over quality" study path. If so, you will study a lot but you won't actually lift your score to the top levels.
You say that you have completed OG10, 12, and 13. If so, then you have done >2,000 questions, but you still want to study more. This tells me that you are
doing a lot of questions but you are not necessarily
learning all you could from these questions.
Read this:
http://tinyurl.com/executivereasoningAnd then this:
http://tinyurl.com/2ndlevelofgmatHave you been studying and learning how to take the test in this way? If not, then you left a lot of learning on the table when you were studying before.
Next, doing practice problems allows you to test your skills, but the practice problems don't actually teach you the math, grammar, and strategies you need to know in order to perform well on this test. So in that sense, yes, you do want to make sure that you are learning the kind of material we cover in our strategy guides (whether you use our books or someone else's). The OG problems are great for practice, but they don't actually teach you how to get better.
What I would recommend at this point is that you take a practice test in our system (everyone can take one free practice test). Do all sections (essay, IR, quant, verbal) and take it under official timing conditions.
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 that, as well as the earlier articles I gave you, 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!)
It may be the case that I advise you to study only certain books - we'll just have to see what the data says.