The audio tour is available for a fee of € 9,00 at

Café Sibylle
Karl-Marx-Allee 72
10243 Berlin
open: mon, thur, fri 10.00 a.m. - 6.00 p.m., tue, wed 1.30 p.m - 6.00 p.m. sat-sun 12.00 a.m. - 6.00 p.m.

You get to Café Sibylle by U-Bahn U5. Station: Strausberger Platz. From there 200 m walking.

Please be prepared to show your id-card or passport at the rental station.