I'm not sure if this is the right place to ask this. What is the salary range at a large firm in Sydney and Melbourne for LLM grads?

Not being from Australia, I have no idea.

EDIT: http://www.llm-guide.com/board/19232 Searching > Me

Hi. There's no real salary as far as I know for LLM grads specifically. If you are a law grad and starting work at a top tier firm in Sydney the average salary range is now about A$60 to A$70. Usually you get the same in your first year whether you are admitted or not as the firms have lock step seniority. You're unlikely to get anything extra for having an LLM over just a LLB.