As we roll around on trips, we use Campground Wifi a lot with our phones and such.

Some campgrounds have decent cabin location to the site's wifi Router set up.   Case in point would be Blue Ridge Campground, which has an owner who cares about stuff like a decent router.   His wifi zone just barely reaches Cabin #4 which is the one we like to use.

Other campgrounds are not so hot, their router is basically for the office folks to use in the office.   They will give you the password if you ask, but the power of the thing is often lacking to go out even 25 feet or so.  

So, I have been investigating them cell phone wifi boosters as a class and have come across a dual band unit straight from China that seems to claim some decent specs and a decent price.

http://www.ebay.com/itm/161908939791?_trksid=p2060353.m2749.l2649&ssPageName=...

Is it for real?    Who knows ???   Only one way to find out and that is to try to order it and check it out when (and if) it ever shows up.

So that is what I did.

I will tell you once it arrives.    I read the stuff and it sounds good, but doing it is believing it.  

You could put it out on the covered deck area and let it project all over your yard and into the stone house.

Stone house -- that may present a problem as stone is very dense and difficult for wifi to go through.

The power lines in the stone house are the same as the ones inside the main house, right?

You could use one of these and bypass all the dense rock issues.   Watch out for the pricing as you need two of them and some of these offerings are just for a single "receiver" unit.  

And, if the original stone house runs a separate meter and junction box from the main house, it won't work as the wiring isn't common between socket receiver in the stone house and the sender unit connected to your router in the main house.

http://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Delectronics&field-k...

Last, you are running a phone based system that possibly isn't normal cable wifi technology but instead perhaps some sort of special phone company technology ......