Removing concrete can be a relatively easy / doable job depending on a number of factors:
1. You are fit and well up to heavy hard work.
2. The concrete does not have steel mesh...
3. The thickness of the concrete.
3. You have a few friends who owe you a favour!
Depending on your time and your budget and willingness to put in a few days of hard graft it might be no harm to get a few quotes....
Top soil was probably removed when the base was being prepared for the concrete so if u lift the concrete you will have a stone base and under that subsoil (hard stoney / clay). More than likely you will need to get some top soil (brown fertile) if you want to grow grass or plants.
u can hire a kango hammer from a hire shop - use heavy duty gloves / eye protection and ear muffs. Once u break a hole in the concrete it becomes easier to chip away near the edges. If u want to leave some concrete for a drive hire a con-saw ( a cutting saw which eats through concrete - draw a line in the concrete and run the blade across the line)...
Best of luck...