Tim,
You want the $89.99 coupler/repeater. And,
BTW, that repeats Power Line Carrier
signals. Nothing to do with RF. With a
house that large, depending on where the
coupler/repeater is relative the the
electrical "center", you may need to put a
power line carrier repeater or two (NOT RF)
at the far reaches of your electrical. But,
wait and see after you put in the
coupler/repeater.
Can't remember for sure, but I think my
coupler/repeater is 3-pin. You need to
check your 220v dryer outlet and match it.
The idea is that the coupler repeater plugs
into the wall and the dryer plugs into the
coupler/repeater as a pass through.
Have fun!