Adding a steering wheel with audio controls to my factory stereo ?

I have a 2009 ford focus. It didn't come with steering wheel controls for the stereo. I do how ever want to put one in but not sure it its even possible. I already have the steering wheel and it is a fit with my car. All i need to know is what kind of control lead i need to connect it to my stereo. I dont even know if my factory stereo can add it. If its possible. what will i need? And im getting an aftermarket sync system, and i also want to connect that to the steering wheel rather then drilling a hole in my dash to add the controls it comes with. is that possible?Adding a steering wheel with audio controls to my factory stereo ?
Read your car manual if your stereo is compatible it will say so if not go buy an aftermarket stereo that is compatible with the steering wheel