Doubt that it's possible to replace a prong - best to replace the connector. A Chassis Plug.
Go to this site...
http://quail.com/iec.cfm
and work out the connector style... C13/14 or C19/20 or C21/22 etc etc - only you can say.
Not unlike the one in this picture link below... a European C13/14 type so probably not the one you need...
http://www.binbin.net/photos/generic/hot/hot-condition-euro-chassis-plug-hot-chassis-plug-.jpg
Then find a supplier - Maplin in the UK have them for just £1.89
Then fit it to the TV
Good luck...
Peccavi
February 2010