My internet speed is so slow. Router too far for ethernet, solutions please.?

I'm on the 3rd floor of my house and the router is 2 floors down and I like to play xbox/ps3 online. I cannot move the systems and my tv down there nor can I move the router up here but the connection is so slow plus with other laptops going on in the house sometimes its near impossible to do anything online. Is there anyway I can improve speed or get a second router or something to transmit the router signals stronger so it reaches better? Please help.