A. your defensiveness should be taken down about 10 notches. losemygrip is giving you solid advice and is clearly trying to help.
B. individuals who completely disregard all forms of art besides painting are very unattractive, unless that individual has an extremely convincing theoretical disposition as to why painting is all that deserves attention... if you are judging art solely according to your aesthetic opinions, you should revise your tactics. unless, of course, you have solid theoretical backing for doing so. purely optical judgements on art have not been well received art historically since duchamp, and frankly, it is offensive (and irritating) to artists who are working in a much deeper conceptual and intellectual environment (the professors and administration who will be reviewing your applications) to do so. this is not to say that you cannot work predominantly with paint. painting has complex philosophies, arguments, and sub-genres; but to be capable of adding to that dialogue, you need to better understand what art is in its contemporary state. that contemporary state has a much broader spectrum then oil on canvas, like it or not.
C. it is great that you are determined and working hard, but if your work is solely aimed at visually impressing grad school review committees, they will see right through it. you should be working equally as hard, if not harder, at developing cohesive intellectual reasoning and a conceptual basis for your work. without this, i think you will be hard-pressed to find quality grad schools interested in offering you admission. that being said, i definitely think that your work, with an open mind and some further knowledge in contemporary art history, will be able to take you to the level you are seeking. obviously you have the mental capacity (brown is no slouch), but i think your biggest opposition (from the minimal observation ive had), is going to be your stubborn/arrogant attitude towards art and your over-the-top defensiveness. art education is thoroughly based in critique.