Request for flat

I am an admitted student at RWTH Aachen University starting my studies in winter semester 2015 for Master program of Communications Engineering in English language. I am coming in Aachen by mid-August and I am looking for accommodation.
I would like to rent a flat near university area (20-30 minutes away in walking is Ok for me), but I am also interested for other locations if they can be easily reached by public transport.
I am interested on personal flats and not shared ones and I do not have any restrictions regarding the total surface. A flat with a kitchen would be a plus, but I would also consider other simple flats if they have other good features related to location, for example.
A furnished/mostly furnished flat is a must for me as I am coming from my home country in Aachen.
I am willing to pay in advance some months' rent as I am interested on keeping the same accommodation during my entire period of studies, which is going to last 2 years.