A halo like the ones on the image is always caused by subtle divergence of light coming from a source. Possible remedies:

• Good quality lenses have anti-reflection coatings on the lens elements to avoid light bouncing back and forth between two element, and lack of this could create this problem. You might need to upgrade your lens.
• Or, check if you are using a filter that is causing this (light bouncing between the filters or filter + front element.
• Or, as AJ suggested, your front (or maybe even/or back) element is not clean - this could even be because of using an oily cleaning fluid!
• Or change your aperture, because the larger your aperture is (smaller aperture number) the more likely is to see this light halo.

Try the last advice first, and go upwards the list :-).

And the last idea is a separate one: maybe the Active lighting on your camera is on super hard and that tries to keep all the detail in very dark and very light parts of your photo. Try to change that to a more conservative setting.