Generally residential solar costs about $3-4/watt.
A roof area of your size could hold up to 30kw or 30,000watts of PV. You probably don't have all this roof area open though and also probably don't need that much solar to zero out the energy for your home.
In my experience a home of your size probably needs about 20kw or 20,000watts to be totally net zero on an annual basis. To provide a more detailed proposal and estimate please fee free to contact me.