Mark and Michael have the right idea.
Take it someplace and tell them that you just want to see if they can recover your files off the hard drive. The error could either point to corrupted sectors of the hard drive or actual mechanical failure. If it is booting into windows my initial thought would be that a repair place should be able to copy the files off the drive still.
If you have any friends that are technically savvy however you could just buy something
like this (
or this if it's an older style hard drive) and then use the drive on another computer as an external drive. They should then be able to pull all your files off and you could save them on a thumb drive or a separate external drive.
That would save you some money, but going someplace like Best Buy and having Geeksquad take care of it would probably be the best bet
