What you need is an extension cable like this one:
http://www.ebay.com/itm/5M-15FT-F-Ty...item43abe0300f
Cut off the female end with the length of cable you need and solder it to the connection point inside the TV set, this would be the neatest looking solution.
Radio Shack may have a cable like this.
Alternately you can buy the crimp on ends from Radio Shack and a cheap pair of crimping pliers and fix the one you have.