Your GMAT score is valid for 5 years and you get your result instantly after the exam. As you will be giving your exam in April so it will be very difficult for you to join any good b-school this season because most of the b-school's application deadline has already closed and even some of them have finished with their second round. By the end of the month of March, most of the b-schools must have already taken out their admission list so you will be left as a choice with very few colleges which are not at all good enough in any way.

So, what I will recommend to you if you are going to take admission in b-school next season then instead of giving exam in April you should give it a little later in the month of Oct-Nov. Till that time you can strengthen up your preparations not only for GMAT but also for other exams like CAT, XAT, MAT, CMAT, NMAT, SNAP. These exams will open up a good opportunity for you to end up in some world class b-schools like IIMs, XLRI etc.

All the best!!