I live in panel-house (cube with concrete walls, reinforced with steel) which is part of bigger block. Recently I have successfully setup wifi network through the flat, but at the recieving end I have really bad reception (-80dB). One problem is the environment and the other problem is interference with other wifi's in the block. The radio spectrum is really overflowing...
I would like to move the AP to better position in flat, but the problem is, it would mean to lay ~12m of UTP cable which would be also mean reconstruction of the flat, to properly hide the cables.
So I was wondering if there is any better option. I'm considering two options listed below:
a) Use power network adapter. This thing is plugged into electric outlet and provides ethernet connection between 2-N places. The manufacturer says it can reach 300 meter, but I'm a bit skeptical about this number. The thing is, that our flat has only aluminum wires, roughly 25 years old... My another concern is security.
b) Second option I'm considering is to use WiFi repeater. I have drawn a simple diagram od flat layout:

The green AP would be the position of the repeater.
What is your opinion on the proposed setup options? Thanks for any feedback.
UPDATE: Some more details. The router I have is Tp-Link WR741ND, running N WiFi, 2.4 GHz. The router is locked by my ISP, so I cannot really tinker with it. 5 GHz is unfortunatelly not an option, because the PCs are laptops without 5GHz capabilities. Plus there are smartphones on the network which doesn't have 5Ghz either.
