You can obtain cash through Your visa or master card. One of my friends has two bank accounts at HBSC, one in the US and one here. He transfers money through these two bankaccounts fast and very cheap.
You may pay everywhere with Your creditcards as well. If You better stay in a hotel or a condo depends on Your economy and preferences.
Very most people who come here each winter choose a condo. If You want I can make a contact to a US citizen who manages a very well located condo building.
There are two preferred areas fro staying here during the winter: The old city, as well called romantic zone or the marina.