Congratulations. That is a great little machine. I too have a Duo 270c. I have a setup with the Duo MiniDock. It looks something like this: http://upload.wikimedia.org/wikipedia/commons/5/53/Duominidock.jpg

Occasionally, these floppy drives pop up on eBay: http://www.vectronicsappleworld.com/collection/articlepics/duo2300/snap11.jpg