i find dps DK's chain pull immensely helpful when i am tanking, he helps bring the farthest caster within reach of my thunderclap and cleave and concussion blow...
whichever direction you plan on going, the first step is always to farm emblems, daily 2 frost and any # of triumphs, to buy your first tier9 232s...
if ever, you'll probably be carried buy your guildmates the first week, while you're still gearing up.
A DW frost tank is ideal for the AOE-fests that are heroics at this point in the game.
The crafted tanking gear in game hasn't ever been cheaper to farm up or buy on the AH on many servers. I'd look into the helm (ilvl 200), wrists (245), chest (245), belt (226), boots (264), etc. if you don't have those slots filled with heroic gear already. Start farming badges to get the off-set triumph shoulders (245) and helm (245) and get the tier nine pieces to fill in where you've got holes. Upgrade each piece as you can to meet your needs.
For weapons, get into the new ICC heroics and get two of the slow (2.60) 1H weapons. Mace from HoR and axe from FoS work well. The trinket from ToC (Black Heart) can be paired with the armor badge trinket (245) and you should be good to go for a bit with those.
Search around tankspot for gemming and chanting threads, they're quite plentiful. Basically you want to increase effective health in any manner possible.
Check this thread for some quick spec and rotation advice.