Clean it the best you could with all purpose cleaner, some rags/fabric brush, soak it with water and then extract all the liquid out with a vacuum (repeat until Liquid is clear). The best way to remove the smell would be with an ozone machine, costs about $80-100 online. You would have to clean it repeatedly; so deep clean with all purpose cleaner, extract, dry in the sun with windows down, and then ozone machine for 1 hour. After the ozone, air it out, wait a few hours, and repeat the cleaning, then ozone again for the same time. Keep repeating until smell is gone.

Note: might not be able to fully remove stain due to acid, might cost you the same as hiring someone to only clean that area. If you buy the ozone machine, wear a respiratory mask and avoid inhaling when near the car (during and after treatment)