Have you tried getting a USB Drive A reader for your PC? That way you could write the design file to the floppy and then transport design to your Viking. It is sooo hard to find a floppy disk drive or floppy card reader for the A drive, tho. All is USB, CDs, and stored external memory sticks.
I hope this might help you--would ask Viking what it recommends, and maybe try Hewlett Packard to ask for input on getting one of those drives for your PC. Should not cost alot of money on the reader as the A drive is not a popular media anymore. Good luck!