I am not a scripting wizard but the scriptbelow creates a global variable (filename) that we use to create a unique file for export on a daily basis.
'**********************************************************************
' Visual Basic ActiveX Script
'************************************************************************
Function Main()
Dim oConn, sFilename, ffilename
' Filename format - exyymmdd.log
sFilename = "\\Dms4\phar\"
ffilename = Year(Now())
If Month(Now()) < 10 Then fFilename = fFilename & "0" & _
Month(Now()) Else fFilename = fFilename & Month(Now())
If Day(Now()) < 10 Then fFilename = fFilename & _
"0" & Day(Now()) Else fFilename = fFilename & Day(Now())
fFilename = fFilename & hour(Now()) & minute(now())
fFilename = DTSGlobalVariables("LogFilePath"

.Value & _
fFilename & ".log"
sFilename = sfilename & ffilename
Set oConn = DTSGlobalVariables.Parent.Connections("Text File (Destination)"

oConn.DataSource = sFilename
' oConn.DataTarget = sFilename
Set oConn = Nothing
DTSGlobalVariables( "fname"

.Value = ffilename
Main = DTSTaskExecResult_Success
End Function