I solve it my self.
In order to compute total sales per day, i have to group the data by date. For specifying period,
i have to use the having clause.
SELECT product_master.ProductName, Sum(billDetails.Qty) AS SumOfQty, bill.Dated
FROM bill
INNER JOIN (
product_master INNER JOIN billDetails ON product_master.ID = billDetails.ProductId
) ON bill.InvoiceNo = billDetails.InvoiceNo
GROUP BY product_master.ProductName, bill.Dated
HAVING bill.Dated Between #9/19/2013# And #9/20/2013#
ORDER BY bill.Dated, product_master.ProductName