Problem with Dates

Can anyone help me please.

I have a table for holiday wherein holiday names and dates are saved in that table(tbl_Holiday).
I also have 2 dates for DateBorrowed and DateDue that are saved in another table(tbl_BooksBorrowed)
and showed in different textboxes. txtDateBorrowed and txtDateDue

If anyone knows how can i add one more day to the datedue if one of the holiday is in between the DateBorrowed and DateDue.