Replace your Antenna
The antennas shipped with most routers are small antennas with omni-directional capabilities. These antennas broadcast a signal in all directions, which can be useful if you need wireless throughout your house, but the range is quite short. A directional antenna can improve range by focusing the signal in a specific way, allowing you to aim it where it's needed. These antennas are often called "high-gain" and the signal increase is measured in decibels (dB).