Extend router WiFi

[stevem5000]

I have a L:inksys WRT3200ACM located on a shelf in the very back of the house....
Front of the house has a fairly weak signal....I would like to boost that signal....

I set up 2 Netgear N300 wifi extender...it helps but my cell phone gets only 2-3 bars at the far end of the house...
In reality from where the router sits to the far front of the house the signal is going thru 4 walls....

I have an 2 ethernet cable going from the router to the other end of the house...one is connected to my Roku and the other is free...
I would like to extend the signal with another router,.but I understand that some routers cannot be used as an extension....Don't know if that's true....

What router would you recommend that I can install to work with my WRT3200ACM to extend the range...

Thanks in advance...

 

[Ikonoblast]

I use an EERO router with three access points and the beacon in the garage. It works great.