I'm an affliction warlock (55/0/16) and a demonology warlock. (0/56/15)
Armory link: The World of Warcraft Armory - Melancholy @ Rexxar - Profile

For affliction:

My main issue here is I'm kinda low on the dps meters. In ICC, I'm getting usually 5.5k-6.3k max, being in like 10th or 11th place in 25mans. I flask up with frostwyrm, use spellstone, etc.
My rotation currently is:
Haunt, Corruption, UA, COA, SB while dots up, drain soul <25% while dots up

I heard of a rotation that's better than this.
SB, Haunt, Corruption, COA, UA.

I feel I should be hitting 7k with my current stats, any tips?

P.S - I'm trying to get my hands on a Nevermelting Ice Crystal, but I'm having no luck.

For demonology:

I'm not too worried about this since it's more of a raid spec for higher survivability. I'm getting 6.3k each run usually. 6.3k on saurfang, 6.3k on festergut, etc. Perhaps it could be higher, but as I said I'm not too worried.