you would need to buy a composite to component up converter.
they do make stand alone units but they arent cheap.
probably a cheaper and easier way is to buy a receiver with upconverting capability. a LOT pre-hdmi receivers (a few years old) have the ability to upconvert composite and s-video feeds to a single monitor out component cable.
some new receivers may still have this feature along with upconverting to HDMI which has become the new thing.