SWR3 have coverage of this German festival.
You can currently watch an interview with Duffy at this link.
Duffy performs at 11:45 German time on Saturday 20th Sept. Some of this may be covered by SWR3 radio at the time.
Duffy's set will apparently be broadcast on the evening of 27th September (at 00.35 German time) on SWR3 Late Night Extra TV Show on a channel which is available in Europe via Astra Satellite (analog and digital). Thanks to forum user "Black" for explaining that the channel is possibly called "Südwest BW" or Südwest RP". If anyone can DVD record this program please let me know!
Also, part of Duffy's set will be broadcast on SWR3 Radio (available via the internet) on 2nd October.
See this link: http://www.swr3.de/specials/newpop2008/service/radio_tv.html
EDIT - SETLIST:
Hanging On Too Long
Breaking My Own Heart
Cry To Me
I am not sure whether this was the entire setlist but it is the tracks that have been broadcast on TV and/or Radio.