GRE® or GMAT® in my case. please help me!!!

[Chocomilk]

Hi everyone, I passed the toefl ibt and now I'm preparing for the next step. I will apply for the master degree in finance. I wonder that whether I should take the GRE test or GMAT test.
1. I don't apply for a MBA program, so is it ok if i take the GMAT test to apply for a MSF program.
2. I tried accessing websites of some US's university, but while some require GRE, some require GMAT, and some accept both of them. The problem is I need to apply for some schools to make sure that I can be accepted by some of them, but I do not have enough time to take both of tests, so what i should choose?

I really need some advices to make a right decision. Thank you very much for your time!