Try the DNChanger Removal Tool along with the Boonana Trojan Horse Removal Tool. It looks like you were suckered in getting a Trojan.
If never find anything go back into System Preferences->Network pane, Advanced button, DND tab and delete what is there and put in only the IP of your router's IP address. Then in your router put in the IP address for DNS of OpenDNS (they have an instructional video) and see if that helps.
Mac Pro Dual 2.8 Quad (2nd gen), 14G Ram, Two DVD-RW Drives, OS X 10.8.3
2006 Mac Book Pro 2.16 (first Gen) OS X 10.7.4
2TB Time Capsule, 2 TB
32G iPhone 4S Black, iPad (3rd Gen) 32G Black