Can the WiFi Extender's Ethernet port be configured as an input instead of output?

I understand that, as shipped, the Ethernet port on the WiFi Extender is essentially just an output in case you have any devices nearby that need to be plugged in.  But I was wondering if I could change the configuration of the Extender's Ethernet port to act as an input instead?

In my apartment, the WiFi Extender's repeater functionality (picking up wireless signal and extending it) is very inconsistent.  The internet signal will constantly drop without any indication, and in general the signal is a bit slower than I'd like.  So my idea was to run a Powerline setup from my Router to the other end of the apartment and hard-wire my Extender directly to that.  In theory, this would feed a much stronger Internet signal to the Extender than having it just pick up and repeating a wireless signal.

I plugged everything in as such, tried the WPS function too, but unfortunately it hasn't worked yet.  Any ideas on how to implement that kind of setup?  Thanks!