Personally, I'm not a big fan of Canons. Both cameras I've owned from them (one film, one D-SLR) proved unreliable for me.
That aside, check your camera dial for a P or an M mode. In the M mode, you can set shutter speed (longer = better for night) and aperture (lower numbers = bigger = better for night). If you don't have an M mode, try the P mode where you can fool with iso settings (bigger = better but more grainy) and turn up the overall brightness.
Not to be a dick, but you know to turn the flash off when taking distance photo's at night, right?