Hi sanghyunp2004,
From what you describe, you essentially "rushed" through this CAT, so you could potentially have scored higher. As a general rule, finishing a section "early" is not a good sign; if you rushed through questions and didn't do enough work (and/or made little mistakes), then you lost points that you otherwise probably could have gained. This is meant to say that you might actually be at a higher 'ability level' than this 630 implies - but we have no way to know for sure UNTIL you choose to take your CATs in a more realistic and Test-like fashion (and commit to maximizing your performance).
You have plenty of time before July, so you could potentially improve a great deal during that time. Since you already have some study materials, I suggest that you study as you choose for the next 2-3 weeks, then take a NEW, FULL-LENGTH CAT and make sure to do so in a realistic fashion (take the FULL CAT - with the Essay and IR sections, take it away from your home, at the same time of day as when you'll take the Official GMAT, etc.). Once you have that score, you should report back here and we can discuss how best to proceed.
Beyond that, I'd also like to know a bit more about your timeline and your goals:
1) When are you planning to apply to Business School?
2) What Schools are you planning to apply to?
3) Going forward, how many hours do you think you can consistently study each week?
GMAT assassins aren't born, they're made,
Rich