Ok so I want to get like a 300 or more GB hard drive for my PS3. However, if I were to get one, wouldnt it get rid of all of my saved stuff if I switched out the hard drive? How do i prevent this? (Like, how do I save all my data?)

If there is a way, what is it and how much does it cost?

Also, where can I buy PS3 Hard-Drives? Do i just buy a regular 300GB Computer Hard-Drive?