Hi rahuldhunki18,
Many Test Takers put too much emphasis on the implied "level" of individual practice questions. The better way to assess your skills and readiness is to see how you perform on FULL-LENGTH CATs taken under test-like conditions.
You say that you're scoring around 580 and that you want to improve that score. We have to look at how you perform 'under pressure' to figure out where you'll find the missing points that you're looking for. Here are some things to look for when you review your CATs:
1) How many Quant questions did you get wrong for a silly/little mistake?
2) How many Verbal questions did you get wrong because you 'narrowed it down to 2 choices and "guessed" wrong'?
These are likely two of the big 'issues' that you're facing. By focusing on (and fixing) these areas, you will likely see the score improvement that you're looking for. With an April 5th Test Date, you have a few weeks of additional study time remaining. You should plan to take up to 3 more CATs during that time and spend the rest of your time working on practicing problems, review, etc.
GMAT assassins aren't born, they're made,
Rich