One of the best MRSA killers is chlorine dioxide. You can run down to you outdoors store and pick up some Portable Aqua chlorine dioxide water purification tablets and mix up a topical solution.
A good starting point would be to put 1 tablet in 250 ml of water. Using a cotton ball you can dab this solution on the area 3 - 4 times a day, trying to achieve a 2 minute contact time with each application.