There are contact details through the Atlantica Hotels website though the hotel won't open until May http://www.atlanticahotels.com/en/ContactUS/
I think you'd be best speaking directly for up to date info (rather than getting last year's prices).

We went last year in August and it cost us 22 euros each to upgrade. Well worth it as to buy drinks at the bar was very expensive.

Prices have gone up way too much for us to consider going this year so we are going to Turkey instead.

You will have a great time.