try:
http://www.allannonser.se/volvo-tgb13.html?sort=last
they come up fairly regularly on there. also put "volvo tgb13 c306 till salu" in to google.se and use the advance search in google to limit your results to the last month or so to see the new ones come up, although you may need to do this on google.co.uk first to remember where it is in advanced search unless you speak swedish.
5 mins of this found me:
http://www.blocket.se/goteborg/Volvo_C03_TGB13_6x6_6_pass_34906030.htm?ca=11&w=1&last=1
luckily Scandinavian's English is usually pretty immaculate. good luck!
