JTSAN I have read that there are replacement antennas available that extend the range of the Air Plus' wifi signal.
Antennas are passive devices.
An antenna gets its gain through directivity. I.e., to be stronger in one direction, it has to be weaker in other directions (conservation of energy).
You can use a higher gain antenna only if it is stationary. If the antenna is moving during the night, higher gain (thus higher directivity) will make the problem worse.
Chen