re: Effectiveness of WiFi extenders...

I use them in my house and have mixed results. I'm using TP Link AV500, which extends WiFi and also creates a "wired" connection over your home's electrical wires. The wireless connection is pretty good at being extended; only complaint is that my phone struggles to jump from one access point to another. I can't really blame this on extender though because it is my phone that is trying to stay on the weak signal as long as possible. (tried several apps, none work well for me with this)

I do love the "wired" connection. I'm getting around 30-40 mbps speeds over wires on the opposite side of the house from the router. I'd recommend this unit for this feature alone. (sorry, this doesn't help your situation, but I thought I'd share for others that might be interested)