Budgeting!!! please help!!?

me and my girlfriend are going travelling and are worried we are shortly running out of time! we travel from the 11th june - 1st october - travelling to bangkok overland to singapour (5 weeks) to sydney overland to melbourne (4 weeks) - new zealand (4 weeks)- fiji (10 days) - los angeles - (9 days) and we are unsure of the budget we require!! please if anyone has travelled to these places, what budjet and information hints and tips will be much appreciated! thanks!!!