Hi Sevil,
To start, many Test Takers spend 3 months (or more) of consistent study time before they hit their 'peak' scores, so it's likely that you just have not put in enough time and effort yet. In addition, the 700+ Score is approximately the 90th percentile - meaning that most GMATers will never score that high (and by extension, a study plan that is 2-3 months long has no way of "guaranteeing" you that type of result). This is all meant to say that you might need to adjust your timeline at some point.
Since it sounds like you're just beginning your studies, then it would be a good idea to take a FULL-LENGTH practice CAT Test; you can take 2 for free at
www.mba.com (and they come with some additional practice materials). If you want to do a little studying first, so that you can familiarize yourself with the basic content and question types, then that's okay - but you shouldn't wait too long to take that initial CAT. That score will give us a good sense of your natural strengths and weaknesses and will help provide a basis for comparison as you continue to study. A FULL CAT takes about 3.5 hours to complete, so make sure that you've set aside enough time to take it in one sitting. Once you have those scores, you should report back here and we can come up with a study plan.
I'd like to know a bit more about your timeline and goals:
1) When are you planning to apply to Business School?
2) What Schools are you planning to apply to?
GMAT assassins aren't born, they're made,
Rich