Your quant score ain't very bad but your verbal score needs to improve a lot. Well, regarding suggestions for book - my suggestion for Sentence Correction would be Aristotle SC Grail. I loved the book and primarily used it.It's 3rd edition has been launched a couple of days back so i am sure that will be even better. For CR, they have recently launched the CR Grail. I don't have any idea how good the book is but it looks promising. You may also try CR Bible if you want. It's a good book too.

Your Hit ratio need to be more than 85% in each SC, RC and CR for you to get a good score. Each of these areas need a different approach for you to get better for which you may follow the following strategy. If you have already practiced some of the sources mentioned below you can get other practice material. If you have any other questions please let me know.

Critical Reasoning (CR)
Preparation: Critical reasoning Bible by PowerScore®, helps with all CR basics.
Practice: All GMAT® Official Guide (OG-12) questions alongside reading the Bible.
Aim: Achieve accuracy greater than 85% in all practice sets.

Sentence Correction (SC)
Preparation: Manhattan® SC 2007 edition, is an amazing book, one may call it the SC Bible as it prepares you exhaustively for SC.
Practice: Read the GMAT® Official Guide (OG-12) for SC & understand the
concepts through Answer Key. Re-do all questions, if possible. Please pay
significant attention to idioms as questions on them are tricky but relatively easy.
Modifiers also require significant attention.
Aim: Achieve accuracy greater than 85% in all practice sets.
Important Tip: Don't spend equal time on all types of SC questions. Practice all of
them initially & identify your weak areas. Focus your efforts more on these for
more robust & efficient preparation.

Reading Comprehension (RC)
Preparation: Read editorials from NY Times® or Washington Post® online or
from other newspapers on daily basis. It helps in building your reading speed. It should
be a daily exercise.
Practice: Practice from all possible sources as a lot of raw practice is required to
ace RCs. Practice at least 100 RCs before you start giving mocks.
Aim: Read easier passage in 2-3 minutes & understand the basic gist of it. If the
passage is really tough you can take up to 4 minutes. Do not rest until you
achieve accuracy > 85 % in all practice sets.
Important Tip: We also advice against jumping to questions first & then looking
for answers in the paragraph. Reading essay first makes answering "main point"
& "summary of essay" questions seem like a cakewalk.

thanks ivyctor..

i have MGMAT strategy guide 4th edition.. can you please let me know if there is any huge difference between 4th and 5th edi. except the ir book and GMAT road map book.

thanks in advance..