IF it were me, I would probably just make a Sub procedure to do a recursive look through all of the sub directories. I haven't tested this, but it would probably just call a sub after line 38 or the word "next". It would probably look something like the following.
CleanSubFolders objFileSystem.GetFolder(strFolder)
Sub CleanSubFolders(Folder)
For Each Subfolder in Folder.SubFolders
Set objFolder = objFileSystem.GetFolder(Subfolder.Path)
Set colFiles = objFolder.Files
For Each objFile in colFiles
If objFile.DateLastModified < (Date() - intDays) then
objTextStream.WriteLine objFile.name & vbtab & vbtab & vbtab & "created on: " & objFile.DateCreated
objFile.Delete true
End if
Next
CleanSubfolders Subfolder
Next
End Sub