BPMan,
Sum your data series on the spreadsheet itself. Then don't show the values thru the chart options. Draw a new text box from the drawing toolbar atop the series. While it is still selected, use the formula bar and place a formula linking to the cell with the sum in it (i.e. =G5) and hit enter. The new total will be in the text box and can be moved adjacent or on top of the bar/column as desired.
Hope this helps.