I'm not familiar with the Xbox saving system, but I once read about exporting Skyrim stuff between 360 and PC.

Here's the reddit thread: http://www.reddit.com/r/skyrim/comments/mfgrp/psa_you_can_transfer_skyrim_savegame_files_from/

A search about FFXIII save files yields this: http://www.reddit.com/r/FinalFantasy/comments/2jew4y/where_are_ffxiii_pc_save_files/ and this: (see comment for link, not enough rep)

So I'm positive you should only have to retrieve the "ff13-00.dat" file from the Xbox using that "Modio" program and place it in C:\Users\[username]\AppData\Local\SquareEnix\FinalFantasyXIII\save

I'm not familiar with the Xbox saving system, but I once read about exporting Skyrim stuff between 360 and PC.

Here's the reddit thread: http://www.reddit.com/r/skyrim/comments/mfgrp/psa_you_can_transfer_skyrim_savegame_files_from/

A search about FFXIII save files yields this: http://www.reddit.com/r/FinalFantasy/comments/2jew4y/where_are_ffxiii_pc_save_files/ and this: (see comment for link, not enough rep)

So I'm positive you should only have to retrieve the "ff13-00.dat" file from the Xbox using that "Modio" program and place it in C:\Users\[username]\AppData\Local\SquareEnix\FinalFantasyXIII\save

For Modio usage, (taken from the first link): Copy the x360 save file from your Xbox to your 360 Formatted USB Drive. Open with Modio. Click open from device locate the save file and open it. Click the file contents tab. Extract ff13-00.dat.