However I think I figured out the way to use Gauth.

First, save the QR code as an image (png).

Go to http://zxing.org/w/decode.jspx, upload. Copy the first 16 characters after secret.

Go to http://gauth.apps.gbraad.nl/, click the plus, paste the secret, and put anything into the other field, and it should give you the code, with a nice countdown timer.