I have just noticed that in OSX 10.9 Mavericks Apple has included Hindu Calendar to be used as System Calendar within Macintosh Operating System.
English Gregorian Calendar
Hindu / Indian National Calendar
to enable Hindu or Indian National Calendar, Navigate to
Apple Menu > System Preferences > Language & Region > Under Calendar Menu choose Indian National Calendar
That’s it, You are done. Now you can see Hindu Year in your active calendars with Hindu Months & Year.
Thanks & Regards