Take the Airport Express train RE7 or RB14, which goes directly to Friedrichstrasse and runs every 30 minutes.
Exit onto Friedrichstrasse and walk north to cross the River Spree. After the bridge take the second street to your right into Johannisstrasse, walk 150 m down the street and you will find us on the left hand side in number 11.
For detailed info and directions please go to bvg.de
You can find the price for a taxi on taxi-calculator.com