I dont get how can you do 2.3k while you have 3.4k ap - your hit over-caped and got not that bad crt %. Should be at least 3k on singel target.
"Screw" all rotations and use brain instead - play to maximalize numbers of SS's while keeping all your DoT's up ofc. (including Unholy Blight).
Change all retarded gems which i mentioned before + your meta gem (grab 21 crt + 3% higher crt hits one), or even +16 ap +12 stams gems (theres is +8 str +12 stam gem).
Change tanking cloak for proper dps cloak - theres 2 of them which are easy to get:
http://www.wowhead.com/?item=37647 or
http://www.wowhead.com/?item=43566 (blue one is better btw)
You got proper Unholy spec so change this shitty sigil and take
http://www.wowhead.com/?item=40875 (takes around 5-10 min to get it if you have epic mount) which is best unholy sigil before
http://www.wowhead.com/?item=40207 atm.
Thats it i think - happy now ?