The currency in Germany is the Euro.
It is rather uncommon to pay with credit cards in Germany and many stores do not accept them. However you can withdraw cash with your credit card at every cash machine. The nearest cash machine to the Audimax can be found at Ulmenmarkt (5 minutes walk). Banks (open Mo-Fri) will also exchange money, though they sometimes charge a fee to do so if you are not a customer.
Computer / Internet
At the Audimax (main venue) and at the Leibniz Institute for Baltic Sea Research (Icebreaker Party + opening presentation) will be computers available as working places as well as to access the internet. Moreover, there will be WiFi available, for which the password will be provided at the conference reception desk.