I forgot to say, at Kalypso you are well placed for the beaches both at Plakias and at Damnoni. The courtesy bus will take you down to Plakias, I think, and Damnoni is probably walkable - take the track off to the right as you're coming from Kalypso, which is below the Damnoni Bay Hotel. The track then goes around the perimeter of Hapimag and down onto the beach. Damnoni beach is lovely although one end has been comandeered by Hapimag. From Damnoni beach, a road along the back of the beach heading eastwards and narrowing to a track, will lead you to the beaches of Ammoudaki, Ammoudi and finally Skinaria (although Skinaria is a very long and difficult walk across the rocks from Ammoudi!)
Cash dispensers - there may be one in the hotel itself but if not, they are available in Plakias (one is by the Alianthos, not sure where the other one is). There are now also travel agencies at Damnoni where I would think money can be changed but again, in Plakias, there are many agencies for this.