All you need to do is present yourself at immigration once a month for the extension of your tourist visa. This will cost 50BZD a month until you have been here six months from the time of last leaving the country. If you do a full six month stretch without leaving, your monthly stamp as a tourist will increase to 100BZD a month. Don't forget and don't be late. They can take it pretty seriously. Immigration for extensions is open from 1 - 4pm Mon to Fri. The office is above Island Perk, which is across the road from Fidos. Both of these are well known land marks and right in the centre of town.