You won't stop them.
If the address is one you can't change, then you need to use a filter - Spamcop is the one I use, and am happy with.
If you can dump the address that's getting the spam, and set up a new one, that'll stop it for a while. Then one of your correspondents will get a virus that will upload his/her address book to the spammers, and it will all start again.