Something to keep in mind when using range extenders/expanders is that they will cut your signal speed in half.
I have two of the RE's. I was not able to get them to play nice with encryption. Fortunately, where I was using them it didn't matter. I was sending the signal between my house and my office at the church next door, and the only way anyone was going to pick up the signal was to sit between the two.
In the past year I had a weird experience, and I don't know exactly what caused it, but I suspect the range expander had something to do with it, but that is just a guess. I was using an access point to send the signal to a range expander, which transfered the signal to a usb adapter. I used this setup for about a year, needing to reboot everything every few months to reestablish the connections. Then it stopped working completely. After a lot of testing and head scratching it hit me that all three devices, access point, range expander and adapter, now had the same MAC number. 2 of the devices had acquired the same number as the third. If I remember correctly, the RE and the adapter now had the same number as the AP. Obviously, you can't have multiple devices with the same MAC # on the same network. While I still use another RE on my network for laptop use in an otherwise "dead spot", I changed the connection in this case to a wireless bridge using 2 AP's. I have my network at home bridged with my church's network, right next door. This actually works better because the networks are bridged, and I can access all computers from any location on either network.