Simply take the battery out of the S3, then put it back in.
Plug the fone into the PC via a standard mini usb to usb cable, then turn the fone on.
By default it should come up on your PC as a mass storage device ... unless KIES is a problem.
Surf through the directories and copy across your photos etc.
I got a price on an LCD repair for an S3 here in Perth WA ... its about $135 all up.
Personally I have had an S3 and they had a shoddy SD firmware chip in them .. .causing the SD memory to corrupt frequently, taking out the contents on the card every time, and often killing the card.
I got rid of mine.