There is a room available for a student in the Demag Studentenwohnheim (nearby Königshügel) from 1st November until December 31st, or perhaps longer if you apply for extra time in a room.
It is quite cheap and the building is in a very good condition; the room has internet, telephone, heating; the price is 155EUR per month (internet included).
Kitchen and bathrooms are shared. The building has a well suited laundry room, study room and sauna. Interested people can reply to this email suggesting the time and date to visit the room on the coming days. This is the website from the Wohnheim: