Hi BrunoInBrunei,
Sorry, I can't quote you exact prices of stuff from memory, but here's some info you may find helpful:
Most of your items on your list should be available here except for kangaroo and goat meat - forget it, you won't get these things anywhere, for any price.
Chicken breasts are available fresh or frozen, and prices vary depending on which supermarket you opt for, but as a guide think of around $5-$8 per kilo. It's not that cheap, and is NOT organic/free range. In fact, ANYTHING organic or free range is very hard to come by, and tends to be extremely expensive. So, where your locally produced chicken is concerned, expect it to be pumped full of growth hormones and antibiotics :-/ That may or may not be an issue for you with your bodybuilding.
Brown rice and brown pasta - readily available and as cheap as you'd find at home, probably cheaper.
Milk - most milk sold here is UHT... fresh milk is available but is very expensive (around $6 a litre).
Broccoli and spinach - both are available fresh or frozen. Fresh is imported, so will be expensive and can be sporadic in its availability.
Tuna, tofu, nuts and oats - all available here, not expensive.
Fresh fish - READILY available here, and very good value, especially if you source from the fish markets. Even frozen is good value; I can buy 3 or 4 LARGE dory fillets for around $4.
Wholemeal bread - be prepared to make your own, I'm afraid; the necessary raw ingredients are all available here. You can buy ready-baked bread, but it is mostly SHITE!!!! PACKED full of sugar and additives, and what they term 'wholemeal' here I would term 'vaguely brown'. Oh, and expect to pay over $2 for a small loaf, even as much as $4 a loaf for something that looks more wholesome.
As for yams, sweet potatoes, pumpkins and green beans, these will be very cheap and readily available, as long as you opt for the locally produced stuff.
Best wishes,
Emma