Wireless question!!

[The Badger]

Hello,

I've just got BT Infinty installed, hitting around 37/40meg. The router is in my front room, I am trying to send the signal directly upstairs. My current adapter is crap.

My question is what's the best way to obtain best signal/speed?
Wireless card? Power lines?

 

[The Badger]

It is the bt infinity router. Why do I need the router and the modem? Can I not replace it with one?

The house is 10 year old, so the wires would be fine, I hope. I don't fancy drilling through the floor to run a cable up.