I came across
this and wonder if its effective. I have Billion router in my room and have lounge PC / HTPC which has Ethernet card. Would this adapter transfer better than a wireless from my room to lounge? and does it work with wireless N routers
As long as you don't have noise filters in your DB, or run X-10 devices to control lights and appliances, you shouldn't have problems with this device as long as you get a 220V version. Speed-wise, it is rated for 200Mbps, while wireless-N is 300Mbps max depending on distance/walls. This device should work with the ethernet ports on the router, not the wifi, so you might be limited to 100Mbps if that's what the router has.
Pricing seems to be $90 to $140 for a pair, you should be able get someone to run a gigabit ethernet cable between the two rooms for a lot less and get better speeds with a 100% chance of it working.