I need a car converted in Calif. so that the brake/gas will be near steering wheel.(mom can not use right leg)

My mom wants her independence after she lost the use of her right leg. I know there are ways to convert her car so that there is a handle for the brake and gas. So far i have only found web sites for ones in Europe. We are in the Bay Area (No California) Does anyone know a local place where they do the conversions and if so, a ball park figure. It is a 2006 Cadilac. Thanks