A:AnswerYou will need a license plate mounted backup camera that comes with it's own dash mounted screen or invest in a new double-din radio with a touchscreen (aren't they all now?)
A:AnswerBest Buy can do that for you but you are much better off purchasing your own backup camera from Amazon as they offer a much larger selection at lower prices.
Note
Make sure that it is a license plate mounted camera as opposed to a low-profile/OEM camera that will require drilling into the body of the car as Best Buy will not do that.
A:AnswerMy technician gave me some broad outlines for a compatible camera but you should check Amazon for a highly rated license-plate mounted backup camera. BestBuy won't mount a low-profile/OEM style backup camera that requires drilling into the body of the car.
They should be able to get it to work with your existing screen.
A:AnswerThey can install the camera. They do not need to know the size of your radio to install the camera. They ha e the cameras at Best Buy or will order b the appropriate camera if they do not have it in the store.