Parse the date as you already do, and then
date= date.replace(2013)
This is one of the easiest solutions using the modules you use.
Thinking about it better, you are likely to run into a problem next February 29th.
input= 'Aug21 3:26PM' output= datetime.datetime.strptime('2013 '+ input ,'%Y %b%d %I:%M%p')
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