What you could look at, look at an ethernet over PowerLine adapter. Something like this.
http://m.newegg.com/Product/index?itemnumber=9SIA4P03FP5055
That basically is supposed to use the existing electrical wiring as a network cable. So you plug an ethernet cable from the existing router into one of the adapters, and the adapter into the wall. Go upstairs and plug the other end into the wall in your room, plug a network wire into it, get yourself an access point perhaps and plug in and set up in order to basically extend the wifi network into the upper area of the house. If all goes well, hopefully that should give enough bandwidth for all of your devices etc.
Can't say I've actually needed to use a PowerLine kit like that before, but the idea seems sound and many of those units seem to have good reviews.