You can't with Outlook alone -- Outlook always wants to print the current
month thumbnail instead of the previous month.  You might want to take a
look at some free Word templates that use your Outlook calendar data to
create a calendar in Word, which you can then customize to your liking.  I
personally use My Outlook Calendar and am very pleased with it -- and it
prints the previous month thumbnail instead of current.  Links to these
templates can be found here:

http://www.slipstick.com/addins/calendar.htm#print