How low is your GMAT score? If it is too low (<650), you may want to retake it. It is possible to transfer when you are in the US and I think the key factor is whether you can get recommendation letters from those professors. The transfer is not the transfer like undergraduate, but rather a re-application.
I want to say something about GMAT. As I said before, GMAT is the facet of an applicant. This is particularly important for Chinese/other foreign students. If you don't have any experience in the US, how can the professors trust your ability? GMAT is not everything, but a good indicator of how good you are in academic performance. Usually for chinese students who want to apply for PhD, >700 is recommendated.