The only way you can get this unlocked now is by using a cable and appropriate software.
However I would not recommend you do this personally - unlike inputting the wrong input code 5 times which just prevents you unlocking the phone remotely, use the software incorrectly and you could find the phone doesn't work at all.
Take the phone to that dodgy geezer down the market, tell him what you've done (blame it on your little brother if you want!

) and ask him to unlock it for you.
He'll probably charge you a tenner - you need to ask yourself whether paying a tenner to unlock that phone is worth it.