Just look up the calendar and find out all the courses that you can take. Choose among them as long as there are available spots and suitable time. Not much you can do but don't worry even you can't find one because it's just 0.5 credit's chance.
you'd better use up the money before the end of winter term. i don't know exactly. my money is still there after 2005 winter term but it is gone after 2006 winter. and, don't deposite too much.