I had a similar experience recently. My spill killed several keys and played havoc with the keyboard backlight. I replaced the keyboard with a new one from Powerbook Medic and I'm back in business!
Cost me about $90 new, which was cheaper than used keyboards from other sites. The top case is quite expensive, so hopefully you won't have to replace that. Does your trackpad work? In either case, you'll probably need a new keyboard because it's sold separately from the topcase. So try that first, and if it still doesn't work you can then replace the topcase.
I have a Santa Rosa Macbook Pro - if yours is only a few months old that's probably a Penryn, and it looks like they're sold out of those keyboards. I'm not sure what the difference is, but I'd email PBM and find out if you really need a Penryn keyboard. Otherwise it'll probably cost you about $125-$150 at another dealer.
I used the instructions from http://www.ifixit.com/
to replace the keyboard myself. Good luck!