You could try hooking up with the Hash House Harriers. They have a somewhat eccentric slant on running (combining it with beer drinking...), but run twice a week on Thursday evenings and Saturdays. If the running is too much, there is a walking group which you can join until you have built up, or mid-way through the run when you have had enough running. Check it out -
http://www.meetup.com/The-Zurich-Hash-House-Harriers/