If I were to choose three individuals to help me survive the Apocalypse; this would be the ultimate team to help us get through it. Even in an Apocalyptic World my goal would be essentially the same as it is today; created a better world for our future generations, while also managing to survive.
#1 Hermione Granger
First and foremost she is always prepared and is always one step ahead of every one else. She is one of the best characters in one of the best adventures we have ever experienced. She can conjure practically anything at anytime, and that includes turning sand into water to keep us hydrated in this Apocalyptic Hell.
#2 Tony Stark With or Without the Iron Man Suit
Tony Stark is essential in my opinion to surviving this Apocalyptic Hell. Not because of the Iron Man suit that would sure come in handy when fending off the cannibals, creatures and other baddies that accompany the desert wasteland we now call home. Since it's now what we have to call home I want Tony there because he understands all the fundamental technology that our pre-apocalyptic world takes for granted, with his expertise we can start a new. Even with most or all of our natural resources destroyed he would find a way to recycle our new world for the betterment of tomorrow.
#3 Tryion Lannister
Tryion is the gangster of our group; not in the common sense of the word but in the figurative form. He is smooth, suave and uses the power of his intellect to out smart and undermine those who oppose him without using force. If there is a chance to avoid a fight he will make an attempt to avoid it, by bargaining or just simply making an alliance that benefits everyone. Once we have an established community, he would be my first choice to lead us from despair.