I am having trouble with my N300 wifi extender

I am not very good with technology and clearly made a mistake. I got the wifi extender to increase overall coverage in my apartment, but now seem to have an issue. I set the product up properly via browser as I was not able to set it up the other way. It showed up as my wifi network name (ex: Wifi_EXT). I was thankful to seemingly get it up and running properly, but think i got carried away when i unplugged it from its original outlet, took it into the room where i was having spotty wifi, and connected it to the TV via ethernet cable. I now cannot find (Wifi_EXT), but rather (TV_EXT). I still have spotty coverage and dont know what im doing from this point forward. I'm not tech savy at all..hoping for some help. Thanks!