Hi! When I was in Vienna two years ago I thought about doing the route and visited the Österreichischer Camping Club shop. It's just outside the inner city, off the Schubertring (http://maps.google.com/maps?f=q&hl=e...,0.012231&z=16). They had a guide book in English for the Danube route. Could be the same one you have, but it might be worth a look if you have the time to check it out. They might have some other resources as well.

Have fun! It's a beautiful area.