German language school (Bremen)

Hi everyone!

I am new in Bremen and although we already moved in, we are still living in Italy/Sweden but will be in Bremen full-time by end of July. I moved here with my husband and two small children and back to square 1. I'm won during which German language school is best to take if you want to have the C-level in the shortest possible time. I've read about Casa and Goethe and wondering which one is better. Or is there any more that anyone knows of? Would be thankful for any information.