Have you thought about one of the ethernet via mains options?
Just gone to that in our flat for my pc...much more stable and 200mbs connection. My ps3 is connected via wire directly to my router so can't comment on gaming via it, but my pc is now connected via the mains ethernet connection and it's loads better! Stable and faster than my wireless.
I have this....
CLICKY!
Maybe not the cheapest solution, but seems rock solid so far from what I've asked it to do.