Parsing Month WorkSheet (one row/Project) into Folder & SubFolders by Project

[u473]

I Need to parse an existing Current Month Worksheet (which data is one
row per project)
into
an External Folder of existing Subfolders by Project (One Subfolder by
Project) and
existing Workbooks by Month.
..
Pseudo code
Loop thru each row of the Current Month Worksheet
Read ProjectID in Current Month WorkSheet
Find ProjectID in external Folder named Projects, Drive F
Open SubFolder for ProjectID
Read Period in Current Month WorkSheet
Find Period Workbook in SubFolder ProjectID
Copy this previous Period Workbook as New Period workbook
i.e. Copy 2011 07 Report.xls to 2011 08 Report.xls and save
Overwrite New Period Workbook with Current Month Project Data
Next ProjectID
..
Sample Data :
Current Month WorkSheet
Period ProjectID Date Field1 Field2
2011 08 Report ProjX 8/31/2011 400 600
2011 08 Report ProjY 8/31/2011 200 800
..
External folder : Projects
Subfolder Name : ProjX
Workbooks Name : 2011 07 Report.xls
Date Field1 Field2 Field3
7/31/2011 300 500 ......
Workbooks Name : 2011 08 Report.xls
Date Field1 Field2 Field3
8/31/2011 400 600 ......
Subfolder Name : ProjY
Workbooks Name : 2011 07 Report.xls
Date Field1 Field2 Field3
7/31/2011 100 200 .....
Workbooks Name : 2011 08 Report.xls
Date Field1 Field2 Field3
7/31/2011 700 800 ......

Help appreciated, as I need to re-familiarize myself with data
exchange between folders.
J.P.