Will an ethernet switch help me?

I have my xbox 360 and PC in my bedroom. I have my modem and router next to each other in a completely different room, and cannot move them. I only have one ethernet cable running from the router into my room. I'm sick of swapping this ethernet cable in order to go online with my pc or xbox. I want to be able to be online with both my pc and xbox at the same time, without comprising either connection. I don't want to use wifi, just a wired connections on both systems. Is this possible with an ethernet switch? If so, does the switch go in my bedroom or the room with the router? I just don't want to have to run another ethernet cable from the room with the router into my bedroom. Sorry for the ignorance, I've never done this before.