I am not sure this will work for what you intend to do, but this is how i would try to solve it.
Create a calculated field to store today's date.. Today()
Then create a parameter, and reference your calculated field under the value list.
List -> Add from Field -> Calculated Field.
After you are done, do the same steps but this time to add the other date field that you having containing the previous dates... This way, the first value in the view should be today's date, but you would still be able to leverage the historical data imported from the other field.
Let me know if that works.