Your Shaman are good to go, but you tank isn't close. Try to get 22k on the tank before you start heroics, the more the better. I'm regularly doing the easy ones now (GD, DTK, UK, and first two of AN) with my tank at 27k and I still have to bomb heals like crazy to keep her alive on bosses.

Here is her armory fi you want to get an idea of what you can get. I have no 10 or 25 man gear, it's all crafted/quest and one piece of badge gear.
http://www.wowarmory.com/character-s...ezim&n=Mevrouw

Drop about 4k gold into your tank and you'll be good to start. This should only be 2-3 days of daily quests with your group. I think my tank had around 22.5k when I cleared my first heroic. Can probably be done with less, but it's tough.