Mate,
dont be to hard on yourself thats a very solid quant score, like amazing, Im in the same boat as you currently trying to improve my verbal and quant, well everything currently. From what I have read about other people's experience and specially about this dude experience under positivie soul who went from 400s or 500s to 700+, he basically went back to the basics on the verbal and tried to understand why each question was right when going through OG. Alternatively I have the
MGMAT SC book which is pretty solid.
But keep chin up... Im sure your dream score is not to far away.
Cheers
JF