If you just made up the address you sent sent your bitcoins to then your bitcoins are gone forever and no one will ever get them. If you copied the address from somewhere else then you might be able to contact the owner and ask him to return the coins.
You cannot manually generate a specific bitcoin address.
Sorry about your loss, I hope you were just testing and didn't lose much.
P.S. If you could go to the Transactions tab, double click this transaction, and post the "Transaction ID" then there is an extremely thin chance you are misunderstanding something and can get your coins back.