Lost databases in SQL Server 2012
It looks like MS has seen this already.  Have you tried running SSMS through 
Right Click - Run As Admin?

http://connect.microsoft.com/SQLServer/feedback/details/198005/not-able-to-access-the-database-model-under-the-current-security-context-microsoft-sql-server-error-916

Also are you logging in as a sysadmin to SQL Server? Do you have create DB rights?  

Edit:
Just saw your original post updated.  It looks like you are restoring to the wrong version for sure.  Consider yourself lucky if that is the issue!!  

Do a SELECT @@SERVERNAME.  What does it return?  Is that the right instance?  Probably not (hopefully).  Try your restore script only after SELECT @@SERVERNAME returns the right info.  Also you might want to use OSQL where you have to state the server name and creds before connecting, that way you know you're at the right one instance.