Okay, I'm no SPriest pro, but here are a few things that I found on your character sheet.
1.) 2% over hit cap. You're losing around 1k secondary stats on that extra 2% hit. Get your hit/spirit/expertise down so your hit is at 15% or as close to 15% as possible.
2.) Power Infusion is a very
situational talent. I used to use it, but picked DI in a movement intense fight, which increased my DPS by ~5k. Been using DI ever since. Also, if Solace and Insanity is not working for you, FDCL is also a good talent, so you might find it a DPS increase.
Otherwise, it would be helpful if you also told us your rotation.
Generally your rotation priority should be:
1.) Devouring Plague with 3 orbs - After you get 3 orbs you should cast DP asap.
2.) Mind Blast/SW:D - Anything that generates Shadow orbs should be your second to top priority. Keep in mind Mind Flay: Insanity though!
3.) DoTs - VT keeps your mana topped and SW:P gets your apparitions rolling. We are a DoT class in the end aren't we? :)
4.) Mind Flay / Level 90 talent (most likely Halo) - Mind Flay is your filler spell, and all 90 talents should also be considered filler spells.
Try sticking to this priority and read up on some shadow articles here, they really are helpful!
Last of all, I recommend you get the addon Halo Pro, if you do not have it already, it shows you at what range your Halo will be pulling max damage. (download it here