Start off by repsecing. If you want to frost tank, my spec is pretty vanilla. I do take Morbiity, but some will say put 2 points in Secent of Blood; franky it's up to you. But your not really close for a tank spec. Other then that, get your self to uncrittable (540 def; I know it's 535 for heroic 5 mans, but just get to 540) and grind, grind, grind. You can get the crafted saronite tank pieces which will have defense on them to get you started. There's also a nice TBC trinket that drops at the end of a quest line in Netherstorm - the quest is from The consotuium near one of the Mana Forges; also the Seal of the Pantheon from reg HoL is loaded with defense. Then you can have the 245 bracers and chest made; and you can buy the 232/245 gear with emblems of triumph. But, you're going to have to grind, there's no easy way to gear a tank; just tank and grind.