It will be challenging to improve that much in that timeframe. You're going to have to go for it and try your best, but I do want to let you know that most people would need more time. Most people study for 3-4 months.
If you haven't studied much yet, read this:
http://www.manhattangmat.com/blog/index ... ould-i-do/If you have already been studying for a while, read this:
http://www.manhattangmat.com/blog/index ... -the-gmat/One of those two articles will help you to set up your study plan. You can come back here and share with us what you are doing for your study plan and we'll tell you what we think.
Also, after you have taken an MGMAT CAT and analyzed it (as described in the above articles), you can come back here to share the results of your analysis. We'll help you figure out what to do from there. (Note: do not simply give us the raw data; we want to hear your analysis of what you think the data means. This is an important skill to develop as you try to get better!)
Good luck!