Firstly it is NH3 not MH3
and it does not have any oxygen atoms dumbster
kill the king
you do a gobal mishin
mine in expert volcano quests
In the sandy plains area 6 I think.
Rare trade with the trader in the village offline
i regret to say but MH3 is only released on the Wii
There are two ways. Wait for the Jhen Mohran quest online then mine on it's back OR... Get to the Tundra/Volcano and then mine in numbers 7 and 5 (Tundra) or 9 and 10 (Volcano)
There are no golden nuggets in mh3, but there is wyverngold and the different eggs. You get wyverngold by killing high level monsters in the deserted island offline. You can get eggs by sending the boats to the treasure areas.
the upcoming God Eater is highly anticipated as it another MH type game. also MH3 on PSP will be release in Japan near the end of the 2010. Hope the US and Europe release comes next.
There really isn't a best sword in mh3. It all depends on what you want it to do. I suggest making a set of sword and shields, 1 with each element. Equip each one depending on your targets weakness. E.g. Qurepeco has an ice element weakness.
After you do accidental investigation (hunt a gobul), then talk to the argosy captain(make sure he went to the hunters realm, then go talk to the wyverian artisan and he'll say he the argosy captain told him how to make long swords. the first weapon you can make is the ananta boneblade. later after you kill lagiacrus you can make thunderclap and so on etc.
i only know for MH3 Tri: Rathalos is known to be weak to Dragon type attacks, the only weapon i know that does this is the switch axe Rough Edge and it upgraded versions. also even though its weakest spot is its head its were most of its attacks come from: fire breath to be one of the many attacks that come from the head its best to attack its legs, only one attack it does which is when it spins around and hits you with its tail but is not very damaging. but the there is also completing a sub quest :deliver wyvern tear of sever the Rathalos tail: send Wyvern tear to RED box and deliver 1 (max to deliver) and go to the camp (were you can 'take a nap') then select 'End via subquest'