oh man! that stinks. Sorry bro. there's always problems with new iOS's. for all big jumps especially. besides being jailbroken, i don't like upgrading immediately for that reason.
apple did push developers to update their apps for iOS 6 and iPhone 5 support, but its never the same without having the actual device/GM copy of it.
I'm assuming deleting and re-downloading the app and rebooting the device didn't work?
the only thing you can do is complain to the developers or try the drastic restore process.