640 - need advices on my application situation- help!

hey all,

i've been now a somewhat long time lurker and needed you guys advices on my current situation.

I just passed my gmat today and got a mere 640 (q43, v35), far from what i was expecting (i was consistently scoring 720+ on every test i did (2 powerprep, 4 (old/new) gmat prep, 3 mgmat, ...). 640 was what i got when i started studying back in sept.. Anyway, as you can imagine, i'm rather shocked.

I'll be applying for a phd for next sept, most of the applications are due for early january.

Now, I need your advices: is it worth it? Do you guys think I have any chances of getting in somewhere?

I was looking at columbia, nyu, wharton because of some professors there that really got my interest but now my options, if any, are much more limited.

I'd appreciate any input! thanks..

p.s. i've already checked to pass the gre but the earliest date is in january in my area and that won't make the application deadlines.