Cables will not do

[Wanderer]

I´m not sure if this will work in your situation, but I recently ran into a cool piece of technology: the Corinex AV200 allows you to send network signals over electricity at speeds up to 200Mbps. It should work up to 200m, so you may be able to cover the 40m to your house, but that all depends on whether and how the two buildings are connected from an electricity perspective. You can get the device at digitalplanet.

I do not have any experience with this technology, so cannot make any statements on whether it works or not, but it sure sounds nice in theory.