Have you considered those terribly cunning but horribly glitchy ethernet-over-mains things? You could use two of them to connect the second device as a simple WAP, rather than a bridge / extender of the first, by using the mains as a virtual ethernet cable right back to the switch/router.
I tried this at a customer's house the other day. Didn't work, but turned out to be because the mains sockets were on different ring mains (I nearly said 'subnets'). So if you want a pair of Gigabit* Belkin Powerline whateverthefucktheyares, let me know.
* Actual maximum speed attainable is 12 bits per second