What do I do? Installing larger hdds into raid 1 computer.

[ingeborgdot]

How do I get a larger hdd into a raid 1 computer? On a computer with a 320gb hdd I want to make it to a 2tb hdd. It is in Raid 1 so do I just add a hdd and let it rebuild and then when that is done add the other 2tb hdd and let it rebuild thus now having a 2tb machine? I have never done this so can anyone help me out? Thanks.