What OS are you running? Under Windows 2000 / XP / 2003 / Vista, you can loop through the files in your batch file and assuming the filename is %%a in your FOR /F loop, and your date format of %date% is U.S. English, you can rename them like:
ren "%%a" "%%~na%date:~-4%%date:~-10,2%%date:~-7,2%%%~xa"