I've been struggling with this thing for a while and I finally found a solution for this issue on .IPA version. Since the cracked IPA version has a same bundle ID as the app store version, backup and restore can be made between the two versions. I used "Apps Manager" for this purpouse, but it can probably be done with other backup managers on cydia.
Here is the procedure:
1. Remove any cracked version or patch of Family Guy app you may have installed
2. Install the app store (uncracked) version of Family Guy and make sure your progress is past the point where it gets stuck in the cracked version. Connect the game with your FB account or create a Family Guy username in the game to make sure your progress is not lost
3. Install "Apps Manager" with Cydia, it can be found in BigBoss repo which is added in Cydia by default
4. Open "Apps Manager", select Family Guy from the list and create a backup of app data:
5. After the backup is created, wipe the existing Family Guy app data
6. Uninstall the app store version of Family Guy and install the cracked .IPA as described on the forum thread
7. Open "Apps Manager" again, select "Family Guy - iOSGods.com" and Restore a backup you created in step 4.
8. Run the game and enjoy.