I use an Edimax WiFi extender c/w five ethernet ports. One port connects to a BT Homeplug (supplied with BT vision box) to link up to BT Homehub upstairs. This gives me 4 ethernet ports plus WiFi at the main tv location and its various input devices. Ethernet via cat5 to TV, Bluray, Humax plus WiFi for Wii, various smartphones (home and visitors), this laptop where I am now typing, two internet radios, and Kindle. Phew!
The WiFi signal from the Edimax fills a blind spot at the back of the house that the Homehub struggles to reach.
The Edimax was around £25 IIRC. Titchy little thing that sits perched out of sight behind the bluray player. I'm not sure of the model as I can't get at it easily. It was a bit of a fiddle to set up at first but once set happily left alone to do its thing, as always RTFM applies. The current model on the edimax site closely resembling the functionality would appear to be EW-7209APg.
http://www.edimax.co.uk/en/produce_detail.php?pd_id=19&pl1_id=1&pl2_id=5
HTH