Dude i empathise with your suitation .I am a non native speaker i took the test on 23rd and scored 710 ( v 41 q 47 )
Trust me dude i suck at both quants and verbal but the only way i improved was to work really really hard .
- To be brutally honest with you the study material you have chosen wouldn't help you to improve your quants score , OG-12 is useless whn it comes to quants what you should do is just go through manhattan strategy guides this will definitely help to score around 44-45 in quants .
-Since your verbal is really low i would suggest taking private tutions for that , the reason i say that is on the verbal portion you need to change your strategies for example during my prep i really struggled with RC questions not because i got them wrong but because i used to waste a lot of time reading and reading passages .I used to take ard 12-14 mins to solve 5 questions on an RC though i used to get them all correct but that was useless , during the final leg of my preparation i changed my strategies i used to lay more emphasis on things like- reading and understanding the structure , reducing the fluff this really helped me save a lot of time on the Rc's that i could use on SC and CR's . This thing alone improved my quants score by 7-8 points
- then SC's it's imperative to understand where to use " THAT " ,where to use " AS", how to read a comma etc.
these things are NOT PRESENTED IN THE MANHATTAN BOOK ! and even if they are it is really difficult to grasp from it .( though i am a big fan of the Manhattan sc book and i highly recommend that book for every gmat aspirant)
Bottom line is if you think you are able to understand your weaknesses then go ahead and work on your own but if you are not able to grasp where you are going wrong then stop speading 250$ and take private lessons.
BTW i did not take any private lessons / coaching classes etc..
But i prepared for ard 2.5 months for this exam in a very structured way .
Anyways if you ahve any further doubts feel free to contact me on facebook (search for -Akshat shrivastava, i am the guy wearing a black shirt clicking his own pic ) and i am NOT A PRIVATE TUTOR !:)
" What [i] do is not beyond anybody else's competence"- warren buffett
My Gmat experience -http://gmatclub.com/forum/gmat-710-q-47-v-41-tips-for-non-natives-107086.html