Nobody can help you if you don't tell them the code !
Try here http://www.deutschepost.de/dpag?lang=de_DE&xml File=828
Click on PLZ suchen ..Click on English in the top right hand corner and then enter the info you have ..The Town Suffix is the Ortzusatz or the area which that postcode covers.Don't forget to put umlauts if they have any in the address or it won't work .