If it were me, I would have the script shell to a program from microsoft called "forfiles.exe". This allows you to do operations on a file based on date and filename with wildcards. That way you all you need is a formatted date rather than a calculation of the last 7 days. Here is the file output with no command-line options:

FORFILES v 1.1 - emmanubo@microsoft.com - 4/98

Syntax : FORFILES [-pPath] [-mSearch Mask] [-ccommand] [-d<+|->] [-s]

-pPath Path where to start searching
-mSearch Mask Search files according to
-cCommand Command to execute on each file(s)
-d<+|-> Select files with date >= or <=DDMMYYYY
or files having date >= or <= current date - DD days
-s Recurse directories
-v Verbose mode

The following variables can be used in Command :
@FILE, @FNAME_WITHOUT_EXT, @EXT, @PATH, @RELPATH, @ISDIR, @FSIZE, @FDATE,
@FTIME

To include special hexa characters in the command line : use 0xHH
.... etc....

It can be found at:
ftp://ftp.microsoft.com/reskit/y2kfix/x86/

BrianTX