I'm not very good at helping people with math, but I'll give it a shot.
Perhaps you can use the physics formula, to figure out initial velocity.
The acceleration due to gravity is . However, you can not simply use to figure out the max height because as you get farther from earth, gravity decreases.
What you need to do is use the gravitational constant, G. It is approximately equal to .
Hmm, this is harder than I thought. I'll have to think about it for a while.