You're too focused on your Internet speeds being the limiting factor to what you're looking for.
Most houses will have internal network speeds faster than their Internet speeds, though it's still useful for networking done in the home, such as file transfer or video streaming.
Those TP-Link Adapters listed above are probably a better option since they're newer technology and better able to handle lower-quality wiring with still delivering the speeds you need.
If you have a cable/co-ax jack at the locations where you'd connect to your router as well as your console/consoles, MoCA would be another option as previously mentioned. Powerline is very dependent on the quality of your electrical wiring, where MoCA is a lot more resistant to interference. Price of entry is a bit higher than Powerline, though I've had numerous years of good use out of MoCA and not a lot of success with Powerline adapters.
For MoCA, you'd need a kit like this:
http://www.amazon.com/Actiontec-Ethernet-Adapter-without-Routers/dp/B008EQ4BQG