Take out the seats, rip up some of the trim, pull carpet out, steam clean twice, throw some scent in it, let dry inside of house. Check for mold smell next day. Make sure you also wipe under the carpet on the base board and everything. You can use some citrus cleaner to give it a better smell than other degreasers/cleaners.
Like said above, yank it all out. Go to a rental store, something like Sunbelt rentals, and get a carpet extractor. Hot water if one is available. If not, use hot tap water in it. Use tide and oxyclean in it and clean your carpet with that once it is out of the car.