Complicated Date sort...

Hi all

I need to sort some data based on the date. An example is:

Season Title On Sale
Fall-12 A Sat 3rd November
Fall-12 B Sat 10th November
Summer-11 C Sat 6th August

It needs to be sorted first by season and then by On sale date. So, the correct order would be C,A,B

I have tried to use the sort dialogue box but it wont let me sort oldest to newest. The On sale column is formated as a date.

Any help?