Try bleach. Dilute it with water in a spray bottle, and spray it wherever the skunk sprayed. You'll want to test it out on a small spot on your floor first if you're worried about it causing discoloration. You'll also want to keep the spray away from furniture. Let the bleach spray sit for a little while before you hose the floor down so that cats and dogs aren't harmed by it when they walk in your garage.
You can also try to get rid of the smell with vinegar. Put bowls of vinegar around your garage, and leave them there for 24 hours. The vinegar will absorb the skunk smell. You can mix the vinegar with baking soda or dish soap or just use it by itself.