Help me to improve my German language skills

I want to practice and improve my German language skills, but I don't have enough time for take a course with specific hours and days.

So what I'm looking for is someone who can spend 30 min per week (or more if I got the time) at the moment that we agree (not always the same time and day) via skype.

I'm not a beginner so it would be easy. With the time what I'm interest to learn is more focus on business so get ready on that.