Buying iPhone 5 outright in Australia?

So i've been looking for stores to buy an iPhone 5 outright, but purchasing an iPhone 5 on Apple store online takes 3-4 weeks to be delivered. And I'm going overseas in 2 weeks, so I'm more than happy if shipping takes no more than 10 days. I'm getting the iPhone 5 as a present for my dad's 50th.

What should i buy among iPad 4; iPhone 5; iPad 2 and iPad mini?

I'm a high school student… Need to buy a new gadget for my Diwali(the biggest festival of India) gift. It must be pretty handy, must be capable of carrying out all the daily life tasks of a high school students. Moreover I have a MacBook Pro 13", so please do not recommend any laptops. The iDevice that i buy would be used by me for a maximum of 3yrs. I want the best among these, price is no point over discussion in this case as long as what you suggest to me is within the price range of $1000(USD)… Guys please suggest as early as possible because I need to buy the device within a week itself!

Added (1). I'm a high school student… Need to buy a new gadget for my Diwali(the biggest festival of India) gift. It must be pretty handy, must be capable of carrying out all the daily life tasks of a high school students. Moreover I have a MacBook Pro 13", so please do not recommend any laptops. The iDevice that i buy would be used by me for a maximum of 3yrs. I want the best among these, price is no point over discussion in this case as long as what you suggest to me is within the price range of $1000(USD)… Guys please suggest as early as possible because I need to buy the device within a week itself!
REMEMBER:- Screen size matters a lot to me!

How to download facebook on my iphone 3g?

How am I supposed to download facebook on my iphone 3g? Because when i go to download it it says 'this app requires iOS 4.3' and I'm thinking there must be a way to download an older version of facebook?

Iphone charging and battery problems?

I recently got a second-hand iPhone from a friend, which she has been using for some years. The big problem is that it charging extremely slowly and the battery depletes with a rate of like one percent per minute while using it. I have 3 apple chargers, also in use for other devices, and they all work, so that can't be the problem.

Is it a problem with the battery? And if, can I replace that battery?