Okay I started with goose island starter kit from northern brew. I am wondering if I should get a wort chiller before I start my brew day?
You don't need one doing extract, but you're going to need one eventually if you move to all grain.
For now you could boil your wort and top up with ice and water.
Also is there a way to help keep beer clear during bottling?
Keep it clear? The beer will clear over 2 - 3 weeks all on its own. All grain brewing requires some type of help such as Irish moss, campden tabs, or gelatin. Extract does not. Either way it will taste like beer.
Is there anything else I might need if I want to do all grain brewing?
Depends on if you go multi-vessel or BIAB. With BIAB all you would need is a bag. Multi-vessel requires a bit more of an investment.
Also what one is better?
A long debated question with no solid answer. As far as I'm concerned I will never extract a brown or porter. I could never have a one hour all grain brew day. So, you see, "better" is a loaded question. I've had amazing extract beers and superb all grain beers. I've also had beers from either method taste like road kill B-hole.
You're best bet is to get several brews under your belt and decide for yourself which method is best for you.