Also, you could do a test and see if the lens is front or back focusing or not. Do a search for FOCUS CHART on google. Download the focus chart and see if your lens is not focusing or not. Followthe instructions as closely as possible for best results.
Edit:
I hope you don't mind, but I downlaoded the JPG you posted and tried out some smart sharpening on it. There was a LOT of room for improvement. So, my question is... did you by chance disable the in camera JPG sharpening? Are you shooting RAW? If in RAW, what are you using to post process your pics? With Adobe Camera Raw, you can get some amazingly sharp pics!
BTW, after the test, I deleted your picture, in response to your desire to the fact that you do not want your pics edited... but I needed to find out or not. I hope that was OK with you.