Given two points how do I work out the angle and velocity needed to fire an arrow?

For a project I am working with a group to make a strategy game, in the game there is an archer unit that fires an arrow, currently the arrow travels in a straight line between the archer and his target.

What I need to happen is for the arrow to arc towards the target in a realistic manner, the archer has data for its own position and its targets position I just need to work out the angle it needs to fire at and the initial velocity of the arrow in order for it to hit its target.

Here’s a picture of what I’m after (sorry its in MS paint).

think like a triangle to get what you want :)))