GMAT Strategy

Hey all,
I am not a newbie here, many people might know, I used some MGMAT books and stuff and studied for 37 days in DEC-JAN and rampaged BTG as well.
Scored a 650(47/34-5.5).

I have applied to a couple of my target colleges and still banking on my essays even with a poor score. But I know I am being over optimistic

Of course if I don't make through :
I am a non native speaker and an engineer. I hope to reach a 50 in quant with a some steady work in 3 months.
That would get me past 700 with a similar verbal score.

But I need a 42-45 score in Verbal. I am already pretty good at it and scored around 40 in my last MGMAT's and GMATprep's.

I need some rock solid guarantee and steady performance in 90 days time(Starting April) so that I do not come back from the test centre with a score below 730 on the 1st of July.

I might reach this target with self study as well.But still a good prep wont hurt me :

Suggestions please.