Hi HoeneSpringsMike,
The Unite as well as all of our MiFi devices were not designed to work with range extenders, more of a short range WiFi device to power a laptop and other near by devices.
You can try and set up the higher range output by the MiFi by following the instructions listed Here. Although this is for saving battery, you want to change the setting to Extended Range or High Power (Verbage may vary based off what revision of the Unite you have).
There are external antenna's you might be able to get to increase the range but these are usually pretty costly.
Hope this helps!