if you are just doing the FILE-IMPORT and the stuff creates new table every day, then what you will have to do is after it's imported, manually add a field called RefreshDate or whatever. create an Update Query to make that field be Date() or NOW() (NOW includes the time too).
if you have an existing table that you are appending the new records to, make a field called RefreshDate (type = date) and set it's default value to DATE() or NOW(). make the format some date/time format. dont fill it in with anything in your query: since it's the DEFAULT value, that's what will fill in when a new record is added.
ok?