You should be able to find lots of places on the Ku'damm (Kurfurstendamm). You should also stop in a local McDonalds, just so you can experience the novelty of ordering a large beer (ein grossest bier) with a Hamburger Royal (they don't call them 1/4 Pounders there). If you have a Berliner Kindl Weiss, ask for the woodruff syrup instead of the raspberry.
Is woodruff the green stuff? I'm looking forward to ordering a Berliner Weiss WITHOUT any syrup - like a local!
Have the beer without any syrup; but be forewarned, it's quite sour. There's nothing wrong with enjoying this beer with syrup. In fact the syrup is German, so that means there are plenty of "locals" who enjoy it this way.