Regardless of how you will approach this, you will have to take two strings and combine them together.
When it boils down to it, you ultimately have two dates:
10:00 - 11:00AM Monday 25th March, 2013
^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Date1 Date2
You can use two separate NSDateFormatter objects to give you what you need.
NSDateFormatter *timeOnlyDateFormatter = [[NSDateFormatter alloc] init];
//... set the format for the timeOnlyDateFormatter here
NSDateFormatter *fullDateFormatter = [[NSDateFormatter alloc] init];
//.. set the format for the fullDateFormatter here
With this, you can use them to create both the Date1 string and Date2 string, then combine them.
NSString *firstString = [timeOnlyDateFormatter stringFromDate:firstDate];
NSString *secondString = [fullDateFormatter stringFromDate:secondDate];
NSString *combined = [NSString stringWithFormat:@"%@ - %@", firstString, secondString];
There's no real pretty way to do this as far as I know.