I took the GRE twice over the course of two years. 620V; 530Q; 4.5W (yikes! but that's higher than the first time I took it: 4.0W). Obviously, do your best on the GRE, but it's not going completely kill your application if your scores a bit low. Statement of purpose, writing sample, letters of rec are way more important.
Let me know if you have any other questions...