Living in the country is the best way to learn its language. It allows you to exercise the basics you learned in academic German courses directly in your everyday life.
The most popular possibility for you to take German courses at the university is probably the international language program which offers courses on different levels year round. Starting with basic language courses where you can learn German grammar to courses like "Mass media in Germany": you will have a huge range of choices. Moreover, there is the possibility for intensive classes before the semester and during your stay.
More detailed information about the German courses can be found on the website of the Division "German as a Second Language and Intercultural Programs".