To get More planets on Spore, you can either:
or with a trade route, you can wait until the alien in the planet you have a trade route with wants to sell his planet to you for millions (i don't advise this because it's really expensive)
Chat with our AI personalities
You don't have to it's automatic.
No Spore is a PC game
Spore GA is an add-on for spore. It is the same game, but it has a separate desktop icon.
The full game of spore is only available on PC and mac, sorry.
You look for it in your programs and find the application SPORE. It will come up.