Eccs pointed out two things which really contribute to the lack of sharpness in your pic. The ISO of 1600 makes it really noisy which can make a normally sharp and well focused image look out of focus unless you are shooting w/ a DSLR that has very good noise control like a Nikon D3. In terms of shutter speed, unless you are using a tripod, the rule of thumb is to use a shutter speed that is atleast the reciprocal of the focal length of the lens you're using. The EXIF info of this pic shows that the focal length was 150mm thus, if you are shooting w/o a tripod, a shutter speed of 1/150 or faster would be needed to avoid motion blur (usually, w/ practice, you can improve on this number).
Things that will improve this shot would be using the lowest ISO you can get by with. I start with 100 and then go up as I need to, but increasing ISO also increases noise. Your aperture was f/7.1 and choosing a wider aperture would allow you to get a higher shutter speed and also make the background more blurred due to a more shallow depth of field.