WiFi is still subject to interference even in the 5 band. I see a neat deal at http://www.amazon.com/dp/B00HSQAIQU/ref=CNET which does double duty.
If you want to try a 5GHz client with Ethernet out, http://www.amazon.com/NETGEAR-Universal-Ethernet-Adapter-WNCE4004/dp/B008LTPFG6/ref=CNET
HOWEVER since this is a 2011 Smart TV I'd forget the Samsung Smart TV and move over to something more current. Either a BD player or Roku.