There is no public transport on Bonaire (no buses), there are taxis. A car can be a good thing to hire (especially if you dive) and also to visit the Park. Besides that there are plenty of possibilities to rent a bike, mountainbike, scooter or motorcycle. Your host will be happy to assist you finding appropriate transport.
If you like to rent a car you can just ask them, they offer several cars with low insurance and full coverage. If you rent your car through them, your transfer from and to the airport is free and your car will be waiting for you at your accomodation. You can ask them for more detailed information or arrange for it while making your reservation.
Our host can arrange transfer from the airport to the cottage for US$ 25.