Favourites lost when updating TomTom app

I have a 16GB iPhone 4 with about 650MB of storage. TomTom released a new version of their app this week, and in order to update the app, I first sync'ed and backed up my iPhone with iTunes. I then downloaded the update in iTunes before trying to sync again. The app didn't sync, probably because of lack of storage on the iPhone, so I deleted the app from the phone and re-sync'ed. The updated app sync'ed correctly after that, but I lost all of my favourites and app settings in the process. I contacted TomTom support about this and there's no way to retrieve them, they're essentially washing their hands off the problem, saying it's an Apple issue.

I can restore my iPhone using the back up I did before deleting the app, but that doesn't really help me in updating the app. Does anybody know whether it's possible to export the favourites from the app, and re-import them after deleting the app and installing the updated version?

Note: I don't want to delete my music and put it back after updating the app. Updating to iOS 7 was a disaster, resulting in my music not sync'ing properly. I could never fix it using iTunes and in the end, I had to use CopyTransManager to manually copy the albums one by one. It took me almost 2 months of manually copying songs from computer to iPhone to get my music back as it was prior to updating to iOS 7 (minus a few albums for which I didn't have enough space), so I am not touching it again ever! (I don't sync it through iTunes anymore).