Disc games (from what I understand) have ISOs, the equivalent of ROMs. (The image on the disc.) Yeah, you can download them, but I wouldn't have any idea where to download them and we can't really tell you. You can play the game on an emulator with your computer (with the game disc), and from what I understand, that is legal. (Of course, that wouldn't help you if you were trying to find the game.
)
Anyway, just keep looking. Used Game stores. You will find it.