Extending the wireless hotspot to a big area or spanning multiple floors of the premises can be done quite easily.
Method 1: Wired (recommended)
One can connect up to four access points or wireless routers to the four fast ethernet ports on the SBHG router to help extend the wireless network. For a farther network range, you can consider using the high performance Wireless-N devices which typically reach 150m~300m.
Configuring the access points or routers should be straight-forward. The bottom line is to give it the same SSID (network name) as the SBHG. However, the channel should be different from that of the SBHG to avoid any overlap; for example, set one on channel 1 and the other on channel 11. If there is a dhcp server built-in, it should be disabled so that it will not conflict with the SBHG's dhcp server.
Method 2: Wireless or WDS (not recommended)
Multiple access points which support WDS (Wireless Distribution System) can be connected wirelessly to form a large wireless hotspot. However, as these devices are repeaters functioning like "relay stations", half of the wifi bandwidth is used to "talk" to the relaying stations while the other half is used to broadcast to the client computers. Also, the distribution topology requires careful planning to prevent undesirable loops in the network.