It was an international language school, Diane, so apart from the German language and cultural studies, trying to learn German shorthand (that's a joke, there's no such thing, the words are so long), typing, etc, I learned a lot from the other students, who were from all over the world, including Japan, Thailand, Australia, England, Italy, France, Iceland, Venezuela, Columbia, Spain and Germany itself. Most of the stuff I learned from them I should probably have learned earlier in my teens, (I was 17) but I was at boarding school and led a very sheltered life - honestly!
Yes, my German did improve markedly, despite the fact that I spent a lot of the time speaking English to my english friend. We also had heaps of fun, travelled around a fair bit, and I even went to my first concert - Elton John in Frankfurt. I can still see him on stage - hard to forget, he had sparkly lime green boots with heels and wedges, a lime green suit with tails, a similar top hat and the huge specs, no doubt lime green as well. Those were the days.
That's all you really need, isn't Colin? I bet you can manage a bit more though, if you were there for two years.