It's not a noobish question, but why not use the built in physics engine?
Add a Physics movement to your objects.
If you need the collision point to create an explosion or something, the halfway-point is a very rough approximation, ie. (Object1.X + Object2.X) / 2, (Object1.Y + Object2.Y) / 2. However this will not
suffice for something as precise for your own physics engine - sorry, you're stuck there, that's what the Physics movement is for