It is up to you to decide which school or program you use to learn the German language. What is most important: that you pass your B1 and B2 exams and that you are fluent enough to properly communicate once you start working at your employer. 

Please research which local language programs exist. We also recommend a virtual language program with a strong and flexible learning methodology. You may choose to study either at a local school or through a virtual program, or do a combination of both.