We can recommend several hotels:

Hotel Bielefelder Hof  (former Mövenpick Hotel), directly opposite to Bielefeld main station - room rates: single room 80,00 € / double room 102,00 € (breakfast included)

ARCADIA Hotel , Niederwall 31-35, next to "Rathaus" and theatre in the city center - room rates: single room 75,00 € / double room 100,00 € (breakfast included)

Hotel Stadt Bremen   Bahnhofstr. 32, in the city center - room rates: single room 64,00 € / double room 82,00 € (breakfast included)

Altstadt-Hotel   Ritterstr. 15, in the city center  - room rates: single room 58,00 € / 68,00 € double room as single room / double room 85,00 € (breakfast included)

Jugendgästehaus Bielefeld  Hermann Kleinewächter Str. 1, close to the city center - room rates: guests over 27 years: single room 50,90 € / double room per person 36,10 € / 3-4 bed room per person 30,90 € - guests under 27 years: single room 46,60 € / double room per person 33,40 € / 3-4 bed room per person 28,60 € (breakfast included) - a special identity card for youth hostels is needed, which is available at Bielefeld University 

Guesthouse of "Studentenwerk Bielefeld"   (48.00 Euro without breakfast (+ 10.00 Euro for a second person in the same apartment / common kitchen with another apartment) in Morgenbreede (on the university campus)  - sorry, already fully booked

For more information about accomodation in Bielefeld: http://www.bielefeld.de/de/ti/uebernachten/

respectively http://www.bielefeld.de/de/ti/uebernachten/hotels/