I'm saving emblems for a chest piece right now cause that's the highest chest I found on the auction house that I can afford. Also I've noticed that armory isn't showing the changes I made yet so give it time please. I should have a full talent build, all glyphs filled out and a 20 defense rate gem on my shoulders.
First thing you need to do is run heroic instances (probably as DPS) to save up and buy your tanking chest/head piece as well as neck piece, trinket and anything else you can purchase with emblems of conquest...
535 defense is the first thing to shoot for if you want to tank heroics.
yes I am running heroics and saving up emblems for a new chest piece since it's my weakest gear right now. I had a helm dropped in H ToC today that is 219 so I'm focusing on chest first then neck then head. I need some help with my talent build and need a rotation. As my gear currently stands my defense is 535, 997 strength and 1850 stamina.