MacBook Pro hard disk failure. How to recover and clean install?
I'm sorry to tell you that your hard drive is dead (or at least is on the way out), and will need to be replaced. If you're not too confident, you can call Apple Care who should be able to recommend a local shop who can sell you a replacement hard drive and install it for you.

Alternatively, it's quite easy to replace the hard drive yourself. If you google it you'll see there's loads of articles and videos on how to do it (here's a good one to get you started). Apple even has instructions on how to change the hard drive in the macbook pro manual, which is definitely worth a read before you crack it open.