Probable Malware/Pop-Up's

In the last 3 months or so, I have been hit with some kind of Malware or Trojan where I get forced ad Pop-up's in my browser (see image) and 50% of the time if I click on a link or button on any webpage it automatically takes me to MacKeeper Site. I seriously need help. I'm in the military currently stationed in Okinawa, Japan and don't have access to a good/reputable Mac Specialist. Any assistance would be greatly appreciated.