kate your problem is your gear pretty much.... You're still in greens and blues for the most part. Go to the auction hacienda and buy as much gear as you can- especially for your tank. You're also over the defense cap by quite a bit - cap is 545.

Toc you have to keep trampling the champions after you have them on the ground. Or they'll slowly try and get on another mount. Just run over them- fight on top of them.

Occulus isn't bad but better gear matters and you have to use the strategies like the ones in the Occulus thread in this forum section.

Ionar- when he disperses - hit follow and run when he does disperse. Go back to the room with the statue guys that come to life- reposition. Also be spread out because he does overload. the thread in this section for Halls of Lightning will help you.

You're hitting some crappy dungeons for multiboxers without gear. Try Gundrak, Drak Tharon Keep.

With each piece of gear it'll only get easier. If you're still having troubles then maybe consider setting up a holy trinity- have one of your rets spec holy and be a dedicated healer.