£5000 is loads in India but nothing in Australia- probably bout the cheapest and most expensive places you'll go. In India I'm living very comfortably on less than £20 a day and a lot of backpackers do it cheaper. In Australia, £12-17 per night in a hostel, few £ travel within cities, £6 for a cheap meal out, £4 a schooner, £35 bus between cities if you make good use of a pass, £3 a day for food if you go very basic.
So like said above, how much time do you plan to spend in each? An if you know roughly when you will go have a look at flights, get a rough price for all of them and take that away from your budget for actual spending budget. Probably take off another few hundred for visas and insurance and I think you need to pay for vaccinations too.
Canada, New Zealand and Australia have working holiday visas so you could consider that