I'm not of the Germanic/Scandinavian speaker so I wouldn't know much about it. But if you want to branch out, those would be the easier first choices.
As for other languages, Chinese/Mandarin is the next highest demanding language based off economy strength. Japanese would be the 2nd choice after Mandarin (Japanese have a high pride of their language).
As the above poster have stated, Spanish due to possible booming of the South American economy. Hindi/Tamil is no where near being a globally spoken language. But as you have said yourself your vision is to move to the Scandinavian countries then your decision should be based on that with an unfaltering will. Sweden populace, as I understand, is versed with the English language. So as a translator you might want to think ahead what language medium would you from and to.
Improving your German would be the wisest decision I would say for now. Chinese is not an easy language to pickup, and even more so for Japanese. (Have a Chinese base currently learning Japanese)