The best advice is to let the director of the school and your teacher know what you'd like to accomplish - whether it's survival Spanish or if you have more specific goals. They will be happy to accommodate your needs if you let them know what your needs are. I've been researching Language Schools in Central and South America, and while all the school's promotional materials seem to sound valid, I don't want to end up getting ripped off. I am interested in attending the language school in Baja California, Ensenada. It sounds great.
Many schools offer credit transfers.
Ask your college first. On the plus side, an agency can handle international payments - many accept credit cards, offers an international point of contact, and has checked several schools. On the downside, many of these agencies require your to prepay before starting a program and some charge a registration fee. Courses can last from one day to several months. Most schools encourage students to take at least one week of classes and preferably two or three weeks for maximum benefit.