Need help with electrical issues 1990 Cadillac Sedan DeVille 4 door

What is your question?

I know nothing about cadillacs. My dad left his car to me. Looks great on the outside and runs great except that the power locks dont work (you have to do it manually), only some of the windows work, the driver seat doesnt work and the cassette player doenst work. Where can I get this fixed in Oakland CA or in bay area? I am nervous to have electrical done by someone that will mess up my car.