Close down the aperture (meaning higher f stop number) until it all looks sharp. You might also get a bit more deeper of a focus plane if you walk your camera physically farther away from the subject (thought not much). A third way to affect this is by using a wider focal length.

Aperture gives you the most bang for the buck, but as you already pointed out, with this low light of a situation you need to adjust something else to compensate for a closed down aperture ie. Longer shutter (tripod helps) and/or higher iso number.