Refund checks are usually sent out after the term starts - so yeah, I would call bay shore tomorrow morning and have all refunds sent to your home address in the US.
As for currency conversion - you'll lose some money converting back from EC to US as the rate going that way is 2.71EC = 1US.
I would also definitely recommend bringing about $50-100US down here and hanging on to it just in case. You'll use EC for all your daily expenses and such.
Yesterday is history, tomorrow is a mystery, and today is a gift. That is why it's called the present.