Search around. Try hard drives or something along those lines... I just reformated so I don't have it on my comp yet... doing updates... but look around that section.
Alright, I've found out the model (I'm pretty unlucky, too, it's a Hitachi 400 gig with a measly 8 MB cache)... can you set up a RAID configuration with one full harddrive, and one new one? Or do both have to be new?