Poor WiFi in living room

[#1]

I have a pair of TP-LINK TL-PA411 powerline adapters upstairs, linking my router (In the room with the main phone adapter) to my PC (In another room). The WiFi connection downstairs in the living room has been great, but just recently it had dropped drastically. I'm looking for something to boost the WiFi signal in the living room.
My initial thought was a wifi extender, but I was told in PC World that it would have to be the same brand (and class - ie 500Mbps) as my powerline adapters. I tried looking online (TP-LINK website) but couldn't find a matching product (there was a "coming soon" product but nothing I could see. Maybe it's not called an extender, maybe it's called something else?
Does the wifi extender/booster/whatever HAVE to be the same make, or can I get another brand - in fact, is this what I should be lookng for at all?? Also, I seem to remember someone telling me that the powerline adapters need to be fitted in pairs. Is this correct?
Regards, and thanks in anticipation for any help offered
Dave

[#2]

Hi
It sounds like your best solution would be to purchase another single TP-LINK TL-PA411 like this one http://www.amazon.co.uk/TP-Link-TL-PA411-AV500-Powerline-Adapter/dp/B0084Y9N4I and you can then add it in to your present system and pair it to your current one connected to the router.

[#3]

That's not going to do much for the wifi on its own. However, plug a wirless access point into it, and that should sort things out.

[#4]

Quote from: tonyAtplus

That's not going to do much for the wifi on its own. However, plug a wirless access point into it, and that should sort things out.

That would be a router type thing, which would also have to be plugged in, right? I was hoping for a one-socket solution to this due to a lack of sockets (I was also told not to plug powerlne adapters into extension cables, rightly or wrongly).
Is there no way that I could plug in an extender of some sort (same make or otherwise) that would connect to the router upstairs?
Forgive my ignorance of the subject.
Dave

[#5]

Quote from: Bernard

Is there no way that I could plug in an extender of some sort (same make or otherwise) that would connect to the router upstairs?

Yes you can do that, you place it between the current router and your living room, just needs a power socket.  See here: http://www.amazon.co.uk/TP-Link-TL-WA830RE-300Mbps-Wireless-Extender/dp/B006BBYXPA/ref=sr_1_4?ie=UTF...

[#6]

Quote from: Bernard

.....    was also told not to plug powerlne adapters into extension cables, rightly or wrongly

Filtered (surge protected) extensions do what they are designed to and attenuate the (interference) signals
Standard extensions are not a problem.