Very easy network question

[Goatboy]

I know next to nothing about networks. Have a router that connects to a PC and a media player in the lounge via wired.

If I wanted additional networked items in the lounge what would I need?

running another (25 metre) cable to the room is not an option.

 

[Goatboy]

I thought it was a switch I needed but couldn't find a basic enough explanation it would definitely be what I need.

My PC/modem/router are located in the kitchen with a cable running to the lounge for the network player. I may get a console at some point in the lounge so wanted to make sure I could connect it to the same cable which it seems I can.

edit: Thanks, the answers here covered what I thought was the case