Minimum connection times are only applicable if you travel on one ticket, which you are not (it would be 90mins in your case, but again, this is not applicable). And yes, Avianca is not checking through on separate tickets, so you definitely have to reclaim your luggage.

Personally, I'm always going for a night stop when travelling on separate tickets. There are plenty of new, nice and affordable hotels near BOG airport, if you don't want to travel into the city center. However, given you depart on LH in the evening, I would actually spend a day in the city (which is nice!).