Hi Ankita,
In this New Revised GRE, there are several important books than the Kaplan GRE book. I not offending the New Kaplan GRE, It's really good, But this time in the New Revised GRE, The Official Revised GRE Guide by ETS is really good to start with the GRE preparation, then you can read the Gruber's New GRE and Manhattan New GRE 8 guides. So then comes the New Kaplan GRE and Barron's New GRE. So its better to go in this direction. . . Oops i forgot the Princeton Review's Cracking the New GRE, It's really good. I've started with that. So many would think that....we can't prepare for New GRE without buying the New Revised GRE books.??? It's wrong perception, recently i was going through a forum in which a revised GRE test taker commented on his preparation. He shared in that forum that, He have prepared with the Old GRE books like, Kaplan GRE 2009 book and practiced with the New ETS Test Prep software supplied by ETS. He commented that the New GRE problems were easier than the Problems in the KAPLAN Gre 2009 book (I wonder how???) . So don't hesitate to read the Old GRE books. Prepare Sincerely and all the Best.