Hi dashang,
Since you're just starting out, you should not be too concerned about this initial CAT score. Those scores can be uses as a way to assess any strengths that you might naturally have, so from these numbers, we know that you have a lot of different areas that you need to work on.
Raising a 240 to a 700+ score will take a serious amount of time and effort on your part. It will almost certainly take longer than 2 months, so you might have to move back your Test Date and adjust your timeline a bit.
You're probably going to need to invest in a GMAT Course of some kind. While certain Courses can be quite expensive, there are LOTS of different options (and they're not all quite so expensive), so you should plan on doing a bit of research into the various options. Most GMAT companies offer some type of free resources (practice problems, Trial Accounts, videos, etc.), so that you can 'test out' a product before you buy it. We have a variety of free resources at our site (
www.empowergmat.com). I suggest that you take advantage of all the free resources, then choose the one that best matches your personality, timeline and budget.
GMAT assassins aren't born, they're made,
Rich