I lived in Germany from '97-'00. The move precipitated my switch from extract to all grain. At the time, quality extract was hard (impossible?) to find in Germany, and very expensive to ship from the States, but getting grain was as easy as driving to the maltster just north of town (I lived in Heidelberg) w/ my 5 gallon bucket. All the pilsner or munich malt I could possibly want for the equivalent of about $0.25/lb.
Hops, yeast, and specialty grains I ordered from the states, usually from MoreBeer or Northern Brewer. I used BrewTek yeast at the time and got it on slants from Brewer's Resource which is now defunct. If you are working for the US Gov over there and have an APO mailing address, any online retailer who will ship USPS can ship you stuff relatively cheap.
While I was there I joined the
Vereinigung der Haus- und Hobbybrauer in Deutschland. It was an incredibly small (for a country of 90 million) national homebrew club. I never made it to one of their events, which happened at least yearly, but I did receive their newsletter and got advice on where to get ingredients from one of the members who lived near me.
There were a couple small homebrew shops within 100 km of Heidelberg and at least a few online shops at the time. It looks like there is more available now than there was back then.