DTS Help - Dynamic Date Parameter

I have a database (Access 97) that is updated by a 3rd party application with tables that are updated hourly throughout the day and at the end of the day. I have managed to create a DTS package that imports all of the data into SQL from the database but I am now stuck as to how to bring in new records each day. There is no 'new record' flag so I can't pull from that - the only way to tag the data is the primary key of date (for the daily tables) or date and time (for the interval tables). I know what I want to do - create a query that determines the maximum date (or date and time) in the SQL table and import only records that have a date (or date and time) greater than that. I just don't know how to do it. Any help would be greatly appreciated as I have been wracking my brain on this for a while. I am new to SQL development but not dbase development.