Thing is, I'm not at all sure what it is that you're trying to do. If you're having trouble getting SuperDuper to work, that's a topic for SuperDuper support (or the SD forums). But if you've got a 500 GB hard drive with a fresh Mac OS X installation and you want to import your documents, settings, etc from the old 250 GB hard drive, you could either erase the 500 GB drive and clone to it from the 250 (again, how to do that would be a SD topic), or you could use Migration Assistant to import from the 250 into the new system on the 500.
If that doesn't help, you're going to need to be a little clearer about what you're trying to do.