you need a piece of kit Made by many firms
Dazzle. V- Stream to name but two
This could consist of a little 'dongle with a USB connector one side and and a set of RCA plugs or a SCART connector on the other a software disk and a slim manual, all packed in a large colourful impressive box in which they will rattle around.
It will cost you £40 or so
Take a look at the E-tailers or Google for Dazzle or V stream