We need a new lock for our door

he locksmith has just pronounced it dead. It's okay as long as one of us stays in the flat at all times - the door can be opened from the inside. The problem occurs when attempting to unlock it from the outside - one of the levers is bent out of place, so no amount of struggling with the key or the door will force it to unlock. And we're talking about a couple of millimetres here - but enough to keep the door firmly jammed shut :-(