Try this
NSString *strCurrentDate;
NSString *strNewDate;
NSDate *date = [NSDate date];
NSDateFormatter *df =[[NSDateFormatter alloc]init];
[df setDateStyle:NSDateFormatterMediumStyle];
[df setTimeStyle:NSDateFormatterMediumStyle];
strCurrentDate = [df stringFromDate:date];
NSLog(@"Current Date and Time: %@",strCurrentDate);
int hoursToAdd = 3;
NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents *components = [[NSDateComponents alloc] init];
[components setHour:hoursToAdd];
NSDate *newDate= [calendar dateByAddingComponents:components toDate:date options:0];
[df setDateStyle:NSDateFormatterMediumStyle];
[df setTimeStyle:NSDateFormatterMediumStyle];
strNewDate = [df stringFromDate:newDate];
NSLog(@"New Date and Time: %@",strNewDate);
Output
Current Date and Time: Sep 10, 2013, 1:15:41 PM
New Date and Time: Sep 10, 2013, 4:15:41 PM