Will my saved games work with a new copy of Skyrim?
Solution 1:
Yes, I have Skyrim installed into my hard drive, bought the DLC from the Playstation Network Store, It works with the install.
It also read my old save perfectly!
Solution 2:
The DLC would work with your old save games. You don't need anything extra to play the DLC.
You would however, need a new copy of Skyrim to play the DLC.