I'm guessing you have a way to get cabling from the room the PC is in to the room the TV monitor is in, as you must have a cable running from the PC to the monitor. As long as that's the case, get a USB wireless mouse and run a USB extension cable from the PC so you can place the mouse's USB receiver in the room with the monitor. If the distance is longer than 5 meters you'll need a hub or powered USB extender.
David
David