Yes you can do what you are talking about... I can think of two ways:
First you can get a prebuilt product specifically designed for this:http://www.x10.com/products/x10_vk53a.htm
(This one will probably break all cordless phones and 802.11b networks within a half a block.)http://www.21best.com/21_best/electr...deoSender.html
Second option, which I think would work better is to go to radio shack and purchase a signal booster. Get the most powerful one you can find. Then plug in signal coax cable on the Input and an antenna on the Output. Then using an antenna (any generic one will work) you can plug this into the laptop. It should work for 30-40 feet on all channels.
If you don't get the range you want or good reception with this you can daisy chain a few of the signal boosters together. ... You can actually run a TV station this way, although you might have a fire risk. or give your neighborhood free cable.
( A friend of mine bought two of the "Wireless DVD" extenders, and modified a CAT5 cable into a coax cable into and out of two of the units [ creating a transeiver on both ends] and made a 10MBit wireless etherneal card a few years ago... the bandwidth range is about the same.)