Take this picture along with the center to center measurement down to Radio Shack and see if they can find anything to match. you also need to determine the diameter of pins which will fit the sockets. Another solution is to cut the plug off leaving as much wire as possible, strip back the cable to expose the two wires and connect your plug of choice found at RS or perhaps Home Depot. Nice having them already in the wall. Good luck.
If it isn't 720p or 1080i/p it isn't HD. If it is 720p or 1080i/p it may not be HD content.