It's always a good idea to use the genuine filter - these are available over the counter at the spare parts/service department.
Castrol is the factory oil - it even says so on the oil filler cap on our car. The service department advised when we were picking up our car that we should use 5w30 Castrol or Mobil. Apparently it is the same for both Diesel and Petrol now days too.
Anyhow, I would recommend using Castrol Edge Sport 5w30. Fully Synthetic and perfect for late model boosted fours.
FYI: The dealer's service department in fact instructed us to buy a bottle of Castrol or Mobil 5w30 to top the car up with as they assure us it will be using up a fair bit of oil while it is new. I'll be getting the oil changed at 5,000km as well - I don't care if they say it isn't needed until 15,000 that's still too bloody long for oil to stay in a fresh engine. It's cheap insurance to just change it earlier.