A "audio video sender receiver" might be what your looking for they are cheap for 480i. They are normally 2.4ghz or 5.8ghz. If you want a high definition version check the professional video stores.
I think I found what your looking for a HomePlug or PowerLine audio video that will run through the whole house. not cheap, They are sold as networking audio/video products.
The only other idea would be the HomePlug or PowerLine products sending a 75ohm TV signal through the house wiring. ATSC wireless repeaters do exist but not really a consumer product. still not cheap.
Thanks for the replies. Didn't think there was a simple or cheap solution. I'll go about it a different way. I knew the question would seem frivolous. Just checking options before going up into the attic.
What kind of a DVR are we talking about, here? If it's a Dish HD DVR, you may be able to get away with using a diplexer. If you're talking about a DirecTV HD DVR, you probably can't.