I mentioned The New Pueblito Paisa Restaurant some time ago. I just posted a video of the place on my blog.
Happened to go back there last week and enjoyed a great lunch. Had the lomito, which is a steak pounded flat and grilled. This is a local Colombian restaurant in San Nicolaas on Helfrichstraat, one block from the end of town, very close to the spot where the autobuses wait against the refinery wall.
Prices here are very reasonable. The lomito platter is something like 20 florins. The chuleta colombinia is another yummy item, which consists of a thin pork chop battered and fried in a garlic combination that will stay with you all day. Spanish skills are very helpful but not necessary. Go early for lunch or late because there is a busy trade with the refinery workers.