How to close wordpad.exe program

Hi have the following script, which works fine:

@echo off

for /F "tokens=1-4 delims=/ " %%i in ('date /t') do (
set WD=%%i
set D=%%j
set M=%%k
set Y=%%l
)

start /w sqlplus myuser/mypwd@mydb @export.sql
start /w wordpad export_%WD%%D%%M%.txt
--How to close the previous txt file
exit

Once the script has finished the export_03072013.txt file remains open and, I would like to close the file.

Can anybody tell me how to do this?

Thanks in advance.

Regards.