Just repeating previous (on rescue) post.
First, just be aware that because your basenji go along with another dog doesn't mean she'll accept a new companion, much less a female. That said, I understand the sentiment.
Have you checked with BRAT (Basenji Rescue & Transportation) or even Florida's rescue, CampBasenji?
http://www.campbasenji.org/
They only list 2... however she has several more that will be ready soon. Pam let's no do gone until she has had them for a while in foster, has a very good idea about any behavior issues and works on them, and their health needs addressed: http://www.campbasenji.org/available-for-adoption/
Brat also only has 2 listed, but I am sure there are more:
https://www.basenjirescue.org/dogs/default.asp
https://basenjirescue.org/dogs-mixes/default.asp
Next, check with breeders... they may still have puppies available, or older puppies that didn't work out for some reason, young adults, etc.
Look to the left of the page on this link and check on every state close enough to be doable. Also, contact your local club as they may know immediately who has available dogs.
http://www.basenji.org/joomla/index.php%3Foption%3Dcom_content%26view%3Dcategory%26layout%3Dblog%26id%3D111%26Itemid%3D94
Affiliated Clubs (ditto the above on checking those close enough)
https://www.basenji.org/joomla/index.php?option=com_contact&view=category&catid=74&Itemid=339