I have had good luck in the past getting them to repair the top case.
My 2007 MacBook (white) suffered from cracks in the palm rest area. Apple was replacing the top case (keyboard, trackpad, and palm rest area) for free. Now that the computer is 5 years old, they may be done with free repairs, but it is worth a trip to see.
I had the computer repaired three times, the first two times they had the part in the back, so I had the computer back in an hour. The last time they needed to order parts, so I had to return 2 days later to drop the computer off, it was fixed by the end of that day.
Hope they you get it fixed for free. If you have any cracks in the palm rest area be sure to point them out and say you heard of others getting new top cases to fix the issue.