Originally Posted by
happypills
There's no need to buy another brake; bicycle brakes can be mounted on either the front or back.
Just cut the cable ties; reinstall the brake you already have at the front of the bike; just shorten the brake cable and housing or alternatively if you're not handy with bikes just have a LBS do it for you; it should take them less then 15 minutes and less then $10.
Well, there IS a reason to buy another caliper. The front mounting shaft is about twice the length of the rear. The OP can use the same lever, but I'd switch it to the opposite side as that's where the front lever is usually mounted.