Fiddy, welcome to the message boards. A pleasure to have you here from Germany. Here is a link of the outdoors directory for Alaska. This will provide several outfitters throughout the state, most which offer brown and grizzly bear hunts. I wish I could give you a recommendation, but as a local I don' t use the outfitters. Hunts will range anywhere from $4000-$12,500 US, which is pretty high priced in my opinion, but with the guide required law for those species, they are able to charge that and usually book years in advance. You might want to look into Canada as I believe it will be considerably cheaper than Alaska, but I at least wanted to provide a site to give you a starting point.
Good luck on your endevours.
http://www.outdoorsdirectory.com/directory/