Nice.
For the second part, there should be an option in the extender for "minimum RSSI /DBm", if there is, set it to -80dbm
Basically its a setting that says " if signal strength gets this low, kick client off " so it wouldnt try to hold onto the connection til the farthest it can, it'll drop it when you get low enough and then it'll switch over to the house cause it will be a stronger signal.
Right now there is nothing telling the extender when to boot the client, so if the client still has some sort of connection, it'll try to stay connected.
FYI:
Generally,
dBm >= -50 dBm = 100% quality
dBm <= -100 dBm = 0% quality
For
RSSI signal between -50dBm and -100dBm,
quality ~= 2* (dBm + 100)
RSSI ~= (percentage / 2) - 100
For example:
High quality: 90% ~= -55dBm
Medium quality: 50% ~= -75dBm
Low quality: 30% ~= -85dBm
Unusable quality: 8% ~= -96dBm