I am trying to determine whether I need a WiFi extender or a router. I am new to wireless internet as well as Mac. I am trying to get a better WiFi signal from my sister's connection (she lives a few doors down). I am able to connect to hers as well as others (unlocked) in the area, however the signals are generally weak and only available in two rooms of my home. I would like to use my Mac in other areas. Do I need a router or Wifi usb extender adapter. I was told by a guy at Office Depot that I needed an extender specifically an Alfa which sounds good based on other Mac forums, but I do not know how to download the driver. The download is available at Alfa through File sharing?? I am clueless how that works. Any advice would be greatly appreciated!