Honestly speaking I do not think is a good idea to retake the exam in such short time.
what you have not been able to do until now is really difficult if not a chimera thinking to jump from 510 to 700 and over.
im not saying this to discourage you but only a fair gauge.
back to the roots, to the basic in particular in verbal part.
Do not esitate to ask
I agree with you....But i scored 700+ not only in MGMAT CATs but also in Veritas
Free test,Princeton Free Test,Platinum GMAT free test,GMATPREP2,Kaplan
,800 score....I exhausted all the free GMAT mock available on the internet.
I want to say 500 to 700 jump in score was not just instant...I did a lot of practise from GMATCLUB forum and OG. Then after i improved score from 500 to 600,600-650 and then 700+...
I am just blank now..