GMAT Strategy

Hi experts,
Please suggest how should I approach GMAT. I am trying to ace this exam since long and the process has been very painful slow and hearting me on all fronts.
I started preparing for GMAT long back in early 2007 after a dissapointing performance in Indian CAT. After seeing the difficulty level of these two exams I thought I will ace the GMAT exam in a month or so. I went to the bookshop picked OG-11 and completed the math on Day1,2 itself. Then I went ahead of scheduling the exam thinking another few weeks will be sufficient. When the date started approaching I found I am not prepared and need some more time, I rescheduled it for a month or so keeping that year PGPX(1-year courses in Indian Universities). I appeared and was thrashed (590).
After this exam a friend cum competitor cum jealous person became aware of my plan, as we both were targeting for some financial certifications and he was already having a very good gmat score. In a bid to confuse me he ensured I forget GMAT for the time being and clear those certifications, as I later realized his plan was to ensure I shoudn't be able to compete with him in those PGPX courses the same year. Though he was more senior to me and well suitable for selection but somehow he might have thought of any possibility of sharing the same course. Anyway, those certifications needed me four long months and it was almost year end, he got his selection. And I started thinking again for GMAT around 2008 beginning. 2008 was a troublesome year and several attempt to sit for the exam failed because of a reason or another. Finally I got sick due to slip disk which was severe and took me month to be thinking again. I took a few month in pain and appeared finally in March 2009 scoring another dissapointment 680(Q-47, V37). Out of several reason job pressure, there was layoff rumor, I got unfortunate job related circumstances just before the exam, back ache was again daunting but I showed courage to sit for the same, I was knowing I am not at my best but thought of seeing where do I stand.

After that fateful March I am again staring at GMAT since, for a last chance, I know I have troubled myself, and every one in my surrounding is disgusted with my efforts to this exam. All these are sufficient enough not to think for the next chance, in case I fail again. My family is fed up with my attempt and efforts towards this exam seeing me doing the same chores for year after year and leaving so many other priorities neglected. I have not been promoted since long, again thanks to this exam. I use to think about GMAT while in office and about office when at home.

So I am in very much in need for experts help about what should I do for this time. I need a 740 at least to keep my hope for a good MBA. Nothing less than this score is going to help me. I have done the following for this attempt:

OG-11, verbal and math supplement.
OG-12: I kept it for late attempts, I did the new Q in OG12 and had the following hit ratio(only new Q not OG-11)
DS-97% PS-99% CR-96%

I did only 3 para from RC and did all correct, has kept 4 passages for date near exam dates. I did a little bad in SC attempted 20 Q and got only 15 correct. After that I thought of doing another round of review and then attempt the remaining 30.

I have done the following:
English Grammar: Wren and Martin
Math: Hall and Knights : Advance and beginner algebra And Geometry books. Plus 10th books for math.

Where I am lagging actually. If I remember my last exam, I did first 15Q of math in 10 minuted then realized the difficulty level is not rising then started concentrating and started panicking. I was knowing in break that I have done bad and verbal too went with all this thinking. Time pressure in verbal is always an issue.

After this exam I attempted two Manhattan tests and got 740 and 710(these are repeat tests as I have already taken them as part of my earlier attempts). I have not tried any other exam.

Thats what I can share about my weaknesses that I am aware of. Please provide your valuable inputs on what all should I do to keep my hope floating.

Best Regards