These functions (dateWithTimeIntervalSince1970, dateWithTimeIntervalSinceReferenceDate, dateWithTimeIntervalSinceNow) accept parameter in seconds.
NSDate *date = [NSDate dateWithTimeIntervalSince1970:(ms / 1000.0)];
You should pass 1273636800.000
NSDate *date = [NSDate dateWithTimeIntervalSince1970:(1273636800 / 1000.0)];