I'm just curious, but isn't translation part of the publisher's job?
Anyway, in case you can't find what you're looking for here, with some searching on the net, you should be able to find a decent professional freelance translator who will do it for you for less than €45. Proofreading would then be around €20 more.
Unfortunately, German is not one of my working languages.
Yeah, me bad. I am publishing it myself through an existing gaming company. They just provide the contacts to the producers in China.