Ok, I have managed to download it and keep the save files.
The first thing I did was find the game folder, "tavern.of.spear", and I copied everything that was in the 'files' folder to the computer. After that I uninstalled the game and downloaded the update, it let me install it. Then I made a new game, saved (right at the beginning when it asks for the name of the character) and came back to the computer to pass the folder that I had copied to the game folder. And it worked.