you could order a new barrel and key from vauxhall,you may need your ownership documents for this so be prepared and you will receive the correct key etc,you don`t say whether the key is broken in or what your problem is but the key should be in position1 then press a small pin in the hole above the barrel to remove the whole key and barrel assy,make sure the spring on the inner rod isn`t broken either,you may want to renew the ign.switch when the barrel is out if there is any doubt.
cdc, December 2011