Hi there,
it maybe too late to answer your questions, but I will avoid those big language schools. They normally charge you a fortune and all students there are mostly rich Americans and Japanese. If you can for instance check hartnackschule in Berlin, where you pay one of the lowest tuition fee but of a very high quality!
I have been living in Germany since 2003 and luckily earned a bachelor's degree at the Humboldt Universitaet. Now, I am in Scotland for my masters degree.