It does NOT matter where the game is extracted, the save data is stored somewhere else in a system defined folder. When you start a new game, a new folder for the that game is created by renpy and the saves are stored there. Now, I don't know if this is goona work or not, but I would:
- Find the old save data (bunch of zip files inside a Renpy folder)
- Copy the whole folder
- Start a new game in the new PC
- Find the new save data
- Replace the content of the new folder with content of the old one
This works on Linux idk if it will work for Windows of Mac