[How adversely would a low GPA affect my chances?]

Which masters programs should I look at if I want to get into Columbia or NYU for my PhD?

[How adversely would a low GPA affect my chances?]

I have a low GPA at a state school (slightly above a 3) and am thinking about graduate school in a year or two. 

I have 2 schools in mind: Columbia and NYU.  I am in love with New York City as a historical subject and a city itself. 

If I did extremely well on the GRE, would I be able to attend one of those two?

Thanks for any help!