Demo question.
 

Well it might be a stupid question but i was wondering, i downloaded the demo, then bought the game. when i log on agian like i was doing the demo i have the full version right?, or do i need to redownload it somewere else?

You just need to enter then numbers from the purchased game into your account; and need to enter a credit card as a means to pay for the subscription after the first free month. No need to re-download, though you might need to patch a little more.

When i look at my account it says that the online digital deluxe and demo are actived does that mean i dont have to put in the key? cause i dont see where i have to.

If it says the digital deluxe is active then you should be fine, if you have any more keys, you can always enter them here: Redeem Key

The demo is the same game as the full game. The only difference is that the demo limits you to the first mission (SS Azure). Once you've entered the retail key (which it looks like you did), everything should look the same except now you have access to the rest of the missions. Your should be able to just continue the progress of your character.