Well, to be precise, you want to increase your wireless range. Increasing your signal strength would be one approach. But not all wireless routers allow you to adjust the signal strength (and that’s often counterproductive anyway).
First follow some basic rules. Placement and orientation can make a big difference. Try to keep the wireless router elevated, at least a couple feet off the ground. The closer to the center of the room the better since almost all wireless routers use omni-directional antennas (the signal is dispersed relatively evenly). Try to keep it out of direct sunlight or any location that would tend to increase the chances for overheating.
If you’ve exhausted all these possibilities, then perhaps the situation calls for more drastic measures.
The simplest solution is to use an aftermarket antenna. While generally cost effective, it doesn’t always help. When they do work, they seem to work best when used at BOTH ends, the router and wireless client(s). But that’s often impractical (e.g., a laptop w/ internal antenna) and starts to lose its cost effectiveness as more antennas are required.
Another approach is a simple antenna modification to make your omni-directional antenna more uni-directional (e.g.,
WindSurfer). It doesn’t amplify your wireless signal, but rather takes the signal you already have and concentrates it in the direction of greatest need.
Another (more sophisticated) approach would be to use a wireless repeater bridge (e.g.,
ZyXEL WAP3205).
[wireless router]<-- wireless -->[wireless repeater bridge]<-- wireless -->[pc]
You would ideally place the wireless repeater bridge approx. midway between your wireless router and most distant wireless clients (although individual circumstances could dictate otherwise). Now wireless clients have the choice to bind to either the wireless router or wireless repeater bridge, whichever provides the strongest signal. The wireless repeater bridge is responsible for relaying traffic back and forth between itself and the wireless router on behalf of its wireless clients.
In the end, most ppl with moderate to severe range problems opt for the wireless repeater bridge. But for mild cases, and to save some money, the other solutions might be sufficient.