After arriving at the airport in Bogota, I took a taxi directly to a Hostel in the Candelaria. The Candelaria is the oldest part of the city and it takes about 30-45 minutes to get there by taxi, if there are no traffic jams. The address of this hostel is: Hostal Fatima Calle 14 (between carrera 2 and 3) in Bogota, Colombia. This is their website : http://www.hostalfatima.com/index.php/mapa-fatima The hostel had wifi, good food and was quite cheap. In any case it is a good starting point if you don't have any contacts there. I only stayed there for two days and then moved in to a friend from Germany, who was living close by in the Candelaria. The Candelaria lies between a relatively safe zone in the north and two rather dangerous zones in the south and west of it. It is quite beautiful and rather safe at daytime. At night you should be a bit more careful, though.
Most exchange students that studied with me at the UNAL were living in northern parts of Bogota and came to university by transmilenio every day. But sooner or later pretty much everyone moved closer to the university. The area around the campus is very beautiful and appears to be quite safe. After having lived in the Candelaria with my friend for one month, I also decided to move closer to the campus. I found an apartment about 150 meters far away from the calle 26 entrance of the campus. To find an apartment I just walked through the streets and looked for posters advertising apartments for students. I then called the number on the poster and arranged a meeting with the owner to have a look at the apartment. I had to pay about 440 000 colombian pesos per month, which was about 180 euros at that time and a normal price for this area. Compared to Munich the rent is actually quite cheap. Consequently, most of the exchange students lived in this area. I can definately advise you to look for an apartment there. However, most Colombian students live in cheaper apartments in other parts of the cities. For the most part they are still living with their families because they can't afford to rent an apartment closer by.