Download the following zip file: VS2012CPPWinForms.zip
Copy the files contained in this archive to the following folder:
C:\Program Files (x86)\Microsoft Visual Studio 11.0\VC\vcprojects\vcNET\
(...or wherever you have installed Visual Studio).
This action will overwrite the file "vcNET.vsdir", so make sure to make a backup of this file in case you want to uninstall.
This will not work for Visual Studio Express 2012, because Microsoft removed the template files from this version of Visual Studio 2012. To make it work on Visual Studio Express, you will need to have access to a full version of Visual Studio 2012 and copy the folders "WinForm" and "ControlLibrary" from the \VC\VCWizards\AppWiz\.NET folder, to the corresponding folder of Visual Studio Express.