I have created a PowerShell script for this, which might be able to help you.
It imports the users automatically from the AD and outputs them to an Excel file, which then Nprinting can import:
Have you got any updates on this? I have the same problem.
Whenever I update the Filters or Groups list the new values are added but the old ones are not excluded. I also tried to import with blank values on Filter and Groups but got no luck, my old values are still there.