A disk image app may be able to make a 100% backup of the drive, after which you coudl format it and sen off for reapir. Once repaired restore the image, boot the PS3 (presuming you get your exact one back again).
log out my PSN ID so the individual thats fixing my ps3 won't be able to read all my private messages, or log into my psn and steal my credit card number etc..
Pretty sure the PSN ID data is in flash memory so your ****ed there even if you do have access to the HDD. Try logging into the PSN via the web on a PC and see if you can modify your details there.