I have generated few fancy bitcoin addresses with vanitygen. I was looking on some webpage how-to-add the address into my bitcoin wallet. I accidentally entered the example private key instead of my generated one. Now I have in my wallet someone else's address and plenty of transactions.

Is there a way how to remove that address from my wallet? I did more actions since the last backup.

The only way I came to is to backup private keys from my wallet and add them to some empty wallet.