Can i score 700+ in one month if i study fulltime?

Definitely. Obviously it depends on how efficiently you study, but people do it all the time. If English is your first language, its pretty easy to improve your Verbal score. However, Quant takes more time because Quant isn't so much about mastering the material as mastering the Quant section of the GMAT (read - training your self on getting to the closest answer fast vs. being able to ultimately figure out the answers). Your best bet is to work practice questions in sets of 37 for quant and 44 (i think) for verbal under the same time constraints that you'll have on the GMAT.

Also if you're planning on top MBA:

While hitting 700 is a great goal, hitting 80th percentile or greater on both sections is far more important, as it enables you to apply to B School virtually anywhere (not to mention it ensures 710+ overall score). Schools analyze the sub-scores in light of your broader application and care about this more than your overall score. 730 overall with an 80/80 percentile split should be your goal, and if you have the time, I'd highly recommend spending extra time studying to accomplish this. That puts you above the average for every school and at the median for the likes of HBS/Stanford. From my experience, people with those scores have the same (if not better) odds than ppl with 750+.

Hope this helps.