Sometimes the existent operation range isn’t enough, or if there are obstacles on the route between the device and the router the distance of operation can be dramatically decreased. In this case You need to increase the sensitivity of the repeater respectively increase the radiation power.
Increasing of the radiation power on the device side isn’t legal and might be a subject only for the qualified electrical engineers. So the normal practice is to redistribute power in the volume. Thus many WiFi devices have an option to exchange their antennas. Than you can replace the original omni-directional antenna by a directional antenna. The power and sensitivity can be increased in a desired direction. The antenna of Linksys 802.11G RANGE EXTENDER - WRE54G can not be replaced for now.