The biggest collection of materials written by the members of the Rote Armee Fraktion (RAF) is available at the International Institute of Social History in Amsterdam. No less than 1,200 documents (20,000 pages) are made available to researchers. The collection includes all publications, interviews, communiqués and other statements of the RAF but also numerous letters, brochures and internal documents. The collection has been put together by Ronald Augustin.
Index of the archives on the RAF available at the International Institute of Social History
The special section of the Social History Portal dedicated to the RAF [documents available online] [in German]
The APO und soziale Bewegungen website aka APO-Archiv [in German]
For a selection of documents translated in English see the website germanguerrilla.com
Fantastic site you possess there.