If you want to improve your quant score get strong in basics. Repeatedly doing the same test won't do any good unless you get an entire set of new questions in each attempt and you do a thorough analysis of all the questions. OG is not enough if you want to learn basics. Get any books which are good in explaining the basics. Apply whatever you have learned in OG problems. Personally i haven't used anything other than MGMAT guides for quant. Go through the book and the 6 mock tests. They are sufficient enough to bring your score to 48/49.