Post it on admission advisory forum.
I think you have a good profile for elite schools. Not sure about Harvard or Standford though, but ask
accepted.com or hjort.
My personal opinion is that you are good for school such as Wharton, with good essays and applications. No need to retake, but if you are really confident to get a 760-790, then I say do it. Don't retake if you want to shoot for 730-740.
but in any case, post it on the admission advisory forum. They will sure to help you.