See the IdeaStorm idea in my signature and add your vote to it as it highlights this exact problem. You essentially cannot get the Reinstallation DVD if you are outside the US unless you call Dell Technical Support and there seems to be a variation in policy regarding the Reinstallation DVD from place to place.
If you need to reinstall Windows 7 on your machine follow my Windows Reinstallation Guide (in my signature) which instructs the user in installing WIndows 7 using downloadable media from Digital River (Microsoft's online partner).