R installation
From AWF-Wiki
Installation of R 3.1.1 for Windows
Download the installer R-3.0.2-win.exe which conains a binary distribution of R-3.1.1 to run on Windows XP and later (including 64-bit versions of Windows). Just run this for a Windows-style installer with standard user rights not as administrator. During setup it is better to change the default installation folder (e.g. to C:\OSGeo4W\bin\R\R-3.1.1) because write access to this folder is needed using the QGIS Processing Toolbox.
