I also have that TP link extender and it works very well. However, if my house were wired differently I would opt for powerline like these as I believe they are more stable and faster and great distance from router is not a problem
Amazon.co.uk User Recommendation
You plug your router in to one and the other in a socket where you are having problems with wifi. You can connect either by wifi or ethernet and should get the same speed as if you were next to the router. Very easy to set up, I have installed them in relatives houses