I am a happy owner of the DG834PN router from Netgear.
It is a little old but I am satisfied from its speed and wifi coverage.
However, I always felt I had to hack this router. The router by default does not support an external antenna. This is fine, since it covers every corner of my appartment. But I had to add an external anntenna connector anyway…
So here it is:
I do not have a way to measure if the signal was improved inside the house, since it was maximum anyway. But I will try around the house and keep you updated!