Need Help to transfer Data from one PS3 HDD to another

hi all,
OK so i have a 120 GB Slim PS3 not modded or anything still got OFW on it and i was wondering if i buy a like 1 TB or what ever HDD how can i get all my Downloaded games (like with PS Plus i got Borderlands Bioshock 2 etc all for FREE) and all my save files for my Downloaded games or game i play on a disks i also have some PSOne Classics on there too onto another HDD

thanks in advanced