Where do I buy tickets for a boat ride from Yangdi to Xingping? How much per person?

It says above 80 Yuan for the trip from Yangdi to Xingping on a fisherman's boat. My elderly father, husband, and two year old son will be arriving at Guilin airport with bags, and want to take a boat to Yangshuo, where our hotel is. What is the best option, and can I book online, or over the phone in English?