I lost both disks when we were rearranging our house. I am wondering, if i buy another disk, if I could still keep all the progress i had made? I had bought the DLC pack for the ROTF one.

 

The disc shouldn't matter. It's a read only format and that's really all the system needs to get the game going. The game saves are stored on internal storage or a USB flash drive you have plugged in, which the disc really has nothing to do with.
You should be just fine.

 

So how do i play them? I have a PS3

 

My apologies, I should've been more clear. You had asked if buying another disc would affect your game saves, basically. I was saying that it wouldn't. On that issue alone, the disc doesn't matter. To actually play the game and use those saves, then yes, you'll need to buy replacement discs. Sorry.

 

Okay now it makes sense. So I buy a new disk, it will work?

 

There should be no issue.

 

And what about my other games, like Lego Marvel Super heroes?

 

Same deal. As long as you have your PS3, any saved progress will be on it. You just need to find/replace your disks.