WA Car accident - legal obligations (payment)

If you're admitting fault then, generally, yes you're liable under torts law for the damages caused. There are always ways to settle a claim, you'll have to talk to the insurer. They are generally pragmatic about things, and will weigh up the benefit of a reduced offer to settle against the time and expense of a civil claim against you. Where that tipping point is, however, is the big question.