Try the vinegar, dish soap, and cold water solution to clean up the stain. Leave the windows open if possible to let the car air out as you work, and make sure to blot up as much excess moisture as you can. If you have a wet/dry vacuum cleaner, you might try using that to help get the moisture out. For an older stain, you might need an enzyme cleaner or some hydrogen peroxide (if you can use it without damaging your upholstery).