I've also been lurking, and not *everyone* is having an easy-breezy time :-)
As for your situation, maybe you could try the open source radeon driver? (Called xf86-video-ati.)
It's 3D support isn't going to compare to Catalyst, but you should be able to configure your monitors using xrandr easily. (Depending upon which DE you're using in Ubuntu, you may have a monitor configuration tool that you can use instead of xrandr on the command line.)
Finally, although you aren't using Archlinux, parts of this wiki may be helpful to you if you'd like to stick with the Catalyst driver.