|You are not going to get that done cheap. Sub titles are a relative simple procedures.|
Voice overs means hiring actors to read through the script and record a brand new sound track. You certainly wouldn't do it as a once-only exercise.
Besides, I and imagine lots of others would prefer German with English sub-titles. Germans speaking English with a German accent can sound a bit comical at times.
Its a bit like listening to Shakespeare in modern English. It doesn't have the same ring to it when done in medieval English.