Vba sum help please

Please see attachements for data...

i have a macro which imports this data periodically (when the macro is run.. another one of these sheets is added) from another workbook and formats it accordingly, end result being what you see in the attachements.. this is run twice a month, around the 15th and the 30th.

the trouble i am having is trying to sum the totals for each new sheet (columns E,F,G)

my original thought was to use a named range, produced by VBA, however i now know that is not what i require. as you can see sheet name "31_07_2011" is more recent than sheet name "15_07_2011"

yet sheet name"15_07_2011" holds the same totals as "31_07_2011"

example code is as follows..

refers to suming the total of hours in column E

Range("$E$4:E" & Cells.End(xlDown).Row).Name = "SumHrs"

    Range("A4").Select
        Selection.End(xlDown).Select
        Selection.Offset(1, 4).Select
        ActiveCell.Formula = "=SUM(SumHrs)"
        With Selection
        .NumberFormat = "0.00"
        .HorizontalAlignment = xlCenter
        .VerticalAlignment = xlCenter
        Selection.Font.Bold = True
        End With

i need something which will sum these columns including the blanks, and will find the end of the data in that column, not the first blank. and then sum the values in that column beneath the last entry of data.

any ideas?

thanks in advance....

Trev.