I applied for graduate school about a week after the deadline for applications had expired because I made a very late change in life-plan. The University to which I applied told me they would accept my late application but I still needed to submit a GRE score... which I hadn't taken since I was pre-med and only had an MCAT. Never mind that the MCAT was far harder than GRE - they wanted the GRE and that was that. Bleh.
Anyway, I went in the next day and took the GRE. Had no idea what was on the thing, didn't know how long it was, or anything. Went in about as cold as could be.
I did alright, not stellar, but not embarrassingly bad, either. Can't remember what score I got but it may have been around what you got. Part of the problem was it was one of the first years they did it on a computer (dating myself), which was great... except the program didn't allow you to go back to problems you skipped. Might have been nice to know that going in. So I got done with craploads of time left over and about 30% of the problems not even attempted.
Sigh.
Point I am trying to make is I still got in. Honestly, unlike medical school where they've got to week 95% of applicants out with standardized tests, graduate schools seem to only care that you have a decent GPA and your coursework is adequate. I already knew the professor I wanted to work for, so that probably helped. I always tell my students to call or email professors as the universities they want to apply to, build a relationship before even applying. I think this really helps grease the wheels.