lol LGW
Hey Fubs,
First I want to make sure your doing this for the right reasons. If your looking for a backup solution if your broadband goes down you can use your brothers, I can see how that would benefit. If your looking at two Internet connections, for the purpose of increasing speed maybe? Unfortunately, two connections will still be two connections, and your internet will have the option of which connection to use.
Secondly, 100 metres is quite some distance for home use. Normally to increase the range of a wireless connection, you would need to put devices in between wireless connections which would act as amplifiers. They will pickup your wireless signal and then boost that signal back out again. Some bluetooth devices have a range of up to 100 metres, for example
Amazon.co.uk: BlueWalker Bluetooth USB Dongle. 100 metre Range! : Electronics & Photo, and you would also need a bluetooth router. These connections are also susceptible to weather conditions. You will find on a wet and windy day, you may loose your connection.
There are of course other solutions, generally used by business's. It's called a Building-to-Building Bridge. Example:
11g 54Mbps Wireless LAN Indoor Building-to-Building Bridge at Academic Superstore