Well it looks like your monitor might also be faulty, but there are two places to check refresh. Catalyst should overrule but check Windows control panel too. In Catalyst Control Centre, Graphics, Desktop Properties, you can check that it's set to 60Hz at 1920x1080. In Windows 7, right-click on the desktop and choose 'Screen Resolution' and then click 'Advanced Settings' 'List All Modes' and select 1920x1080 True Color (32bit) 60Hz, OK and apply and see if you display jumps back to normal. When I go back to this it again has 59Hz highlighted, but the display is good and I haven't had a problem for months.
Edit: If you are using HDMI, use a cable that supports HDMI v.1.3(b) to support full HD resolution (1920x1080).