when you deliver a statue you receive the reward depicted on the corresponding Zeus tile.
I read in the forum that the companion card must be of the same color than the statue delivered but I can't find anything in the rules saying that you can't take one from another color.
On page 6 under "Statue":
Reward: Take a Companion Card of your choice from the General Supply that matches the color of the Raised Statue.
I have one more question about Heroes cards : when you choose one can you discard all your injurie cards of the same color or the bonus is only applicable for the new injurie cards drawn ?
The rules on page 8 say that from now on you may discard all wound cards of that color. It doesn't say that it only counts for newly obtained wound cards. Thus, I would say, you discard all of that color immediately and all new wound cards you obtain in the future.