John,
Sounds OK to me.
I have my router out in my workshop in behind the house and it covers pretty much all of my property.
When I first installed it, I had the opposite problem to you, in that I ended up turning it's transmit power down to about 70%, the less people that know you've got a wireless network, the better.
One thing I have learned with routers over the last few years, is to protect both the phone line and the mains input with surge diverter units, I'm on my fourth router in about 3 years due to voltage spikes and other such things.
One thing I cannot stress enough, is to use some sort of security on your network, WPA2 is the hardest to hack, so I'm told, but even just hiding your SSID can help make your network a bit more invisible to those outside your network.
