You can connect to another computer, create a new user account, set up your iTunes account, back up manually and transfer your purchases. After you replaced your device, connect it to this computer and restore it from the manual backup.
If you're running iOS5, you could also use iCloud to back up your iPod.
Apple does not save your data. You can try to get it repaired by some 3rd party company, but I'm not sure if they will backup your data.