Can I upgrade the steering wheel for a 2007 Ford Focus to add more controls?

Steering wheel controls are very convenient but, generally speaking, they’re not something that can be retro-fitted. Even if there was higher specification Focus with steering wheel controls as a factory fitment (and the Ghia version of your car did) it’s unlikely your car would have the wiring and electronics to adapt the steering wheel from that model. Even if the wheel could be physically fitted, the functions wouldn’t be accessible to the rest of the car.