I LOVE Doctor Aphra. To get the full story you need to read the Darth Vader and main Star Wars series, they crossed over into each other before Aphra became a Vader spin off. All three books are excellent. Aphra and the murder droids all debut in the Darth Vader series.
I confess I did pick up a few Doctor Aphra graphic novels at the library after reading a rave review of them somewhere. They were fun.
(Unfortunately, our library didn't have a complete set so it was a bit confusing. They had Volume I and 4, but not 2 or 3, or something like that.)