1) Use The DMax function to find the highest date in your current database, then use that field in your append query.
Code:
Dim MyDate As Date
MyDate = Dmax("TransDate", "transDetail")
http://www.techonthenet.com/access/f...omain/dmax.php
2) The one thing I would caution you is to check your data carefully, and make sure you are timing your imports correclty. If you were to import today's data during the middle of the day, then when you next imported, you wouldn't get the end of today's transactions unless your transaction date is a timestamp and your MyDate field was also a timestamp field.