With a cloak and boot replacement (buy the frost emblem cloak and get the crafted boots or the boots from (H)FoS) you should be fine a good bit into ICC 10. Once you get the upgrades you'll want to gem them and chant them properly, and by that I mean epic gems.
I'd also suggest looking into the armor trinket, 245 helm and 245 shoulders from the triumph badge vendor. They're easy enough to earn with heroic farming and the 245 helm with raise your expertise level.
Your hit is good. It's most important to ensure dark command lands on the boss swapping fights. If you're finding your taunts aren't landing, use death grip. Worst case scenario, glyph dark command for that fight. Expertise is OK. The 245 helm will help. The Tier 10 legs and/or legs from Saurfang will also help. Shoot for 20 EXP as a blood DK, more doesn't hurt.
Spec is OK. No glaring problems. Just stick with what works for you. Right now you're sacrificing a little extra threat for more mitigation and that's OK while you gear up.
Replace the glyph of corpse explosion, you don't even have it talented. I'd recommend replacing with Horn of Winter.
DnD glyph is your choice to maintain. 2P Tier 10 will have the same effect, so you might want to think about replacing it sooner or later. I really only use DnD as a trash opener on my DK. Once you get both diseases up and spread around you can work in frequent blood boils to hold their attention. Glyph of disease helps facilitate a quick respread of the disease for more blood boiling fun.