You can do quite a few methods, I personally would set this up as a scheduled query (or DTS Package) in SQL to dump the data to the shared folder so it can be done in one go.
Another method again still using 2 steps would be to set a scheduled task within Windows for your batch file to run at a set time after the ePO server task.
Can't remember of top of my head if you can configure the ePO scheduled export to a UNC path but I'm assuming not as you stated it can only be local drives.
Thanks Ian for the answer.
The second method is very simple but i don't know how much time take the export query. There is a lot of data.
The first method seems to be better than the second but more difficult to implement. I try it.
I'm waiting for any other ideas.