What's the best way to go back from 13.1 to 12.3?

Hi, I've spent weeks trying to get everything working again since upgrading to 13.1 from 12.3 using the 13.1 x86_64 cd. My sound no longer works, mythtv no longer works, and the only way I can get the system to reboot or shutdown is by using the reset button or power switch, because the system hangs unless I boot to the 3.7.10 kernel from 12.3. I've submitted bugs but the future doesn't look good for getting them fixed anytime soon since TV cards are a low priority. I just want to have a working system again without starting over with a fresh install of 12.3

Thanks for any help.