It sounds like your most important connections are in the basement and
you may want to connect multiple computers there. So you probably
want your router in the basement in this case.
Try doing this in steps:
1) Get a Buffalo WHR-G125 and put it in the basement connected to the
modem. Connect desktops by ethernet cable to the router there or use
wireless if you prefer. Set the antenna at an angle so that the
sides of it (not the tip) face the area you want to connect to
upstairs. Then test upstairs. If all is well, then you are set.
2) If you don't get good enough reception or coverage in the rest of
the house, but can get some marginal reception, then try adding a
reflector to the antenna:
- make your own following this easy pattern:
http://www.freeantennas.com/projects...te2/index.html
3) If the reflector doesn't get you enough coverage, then use your AC
outlets to extend your range with a set of these:
http://www.netgear.com/Products/Powe...rs/XE103G.aspx
Then you can connect a second AP (same buffalo router) to the XE103
upstairs and set it on a different channel to cover your whole house.
In sum: solution #1 or 2: One router with or without reflecter $45
gets you partial coverage, possibly enough.
solution #3 Two routers plus powerline adapters: $200 gets you
total coverage.
Cheers,
Steve