I went to Colonia, a few weeks ago. I bought my ticket from Seacat online. I sailed both ways on a Buquebus vesselThis was my second time there in 11 years of living in BA. Don't plan to stay there too long, as the town is B-O-R-I-N-G ! You can withdraw up to US$1000.00 per day from bank ATMs.
Bon Voyage.