This question seems to be asked once every couple of days.
Firstly ignore target dummy dps, it means little due to the fact the sample data is highly corruptable and target dummies hardly simulate boss encounters.
Instead target dummies can be useful for practicing but it isn't the raw dps figure you should be analysing. You should be checking to see how often you are casting MB and how close is that to 7 seconds? Are your dots up 95% of the time? How many MF ticks are you getting per second? If you can manage a MB every 7.2 sec, dots up 95% and MF ticks every 1.5 sec you're pretty much at the limit of your rotation/priority.
Next is gearing appropriately, you should be familiar with
www.shadowpriest.com and the best gear thread. From a critical point of view your gear is on the poor side, whether that is due to poor choices or lack of opportunity I can't say. Most spriests will tell you that T7 is garbage, only the Hands, Head and Shoulders are worth anything and at the really top end gear you only worry about the Hands. You also haven't used the best enchants possible, this all comes down to how committed you are to doing the best possible dps. You could use a 63 spellpower enchant on your weapon, your wrist could use a 30sp enchant, there is a better inscription for your shoulders, your cloak is unenchanted (as a tailor its not hard to put a lightweave embroidary on it). Your rings don't have 19sp and those mats aren't expensive.You get the point.
Your spec looks fine, there is a 2nd spec that is worth some merit but i'd suggest you keep what you have until you feel more advanced. The 2nd spec is to drop the 5 points in Spirit Tap and put them into Shadow Affinity & Imp VE... but again I wouldn't change it for now.