Whether this is the best way or not, here is a solution.
I would change the way you enter the criteria at the moment. I assume you have the standard criteria pop-up box from within the source query to enter your date range.
i would change this so that the values are grabbed from a form where you enter the values required. Then call these values from your query using the lines(You need to edit accordingly):
forms!Dataform!ControlName
As for remembering the last dates used, you could create a table to store the combinations of dates used so far, giving you a record of what you have done in the past. The form can then pull data from here to display the last date range used.
hope this is what you were after
Ian