When you take night shots, shoot at the lowest ISO you can. Just 'cause its dark out, doesn't mean you need to up the ISO.
Use a tripod (which I'm sure you did for this shot) and set your F-stop at a mid-range setting for your lens…
right now i have a lumix(panasonic) ten meg camera with aspirations for getting a canon 40d or a 1d. i now have a canon 40d and use a tamron 18-250 zoom and i also have a 50mm 1.4 prime and use a 580exII flash