Hi,
with RU13 WS2012 is supported, but the new installer is not yet released, as you can see from this page:
http://support.microsoft.com/kb/2669061
"The Self-Healing Setup (SHS) that is needed for the installation on Windows Server 2012 will be published along-side Microsoft Dynamics CRM 2011 Update Rollup 13 on Microsoft Update mid to late April, 2013."