HD noise
On the MBR the hard drive should be whisper quite. If you put your ear on the front right palm rest and confirm what you are hearing is the hard drive, you should clone the drive to an external now (use SuperDuper or some such).
If you have BootCamp, WinClone your BootCamp partition to the OSX partition before SuperDuper to an external.
If you have done this your are safe from data loss and having to start from scratch.
Shop for a new hard drive (2.5" SATA 5400 RPM or 7200 RPM). If you are the least bit mechanically inclined, do a web search of for MBP hard drive replacement instructions and go for it. Other wise ask around and find someone that has experience.
There is debate whether changing the HD voids the Apple warranty, so if this is a concern you will need to go through Apple for the repair.
Neil