You poor thing! Both my son and my daughter have thrown up in my car several times now. The best product that I have used so far to clean it up and get that nasty smell out is Dr. Bronner's liquid soap. It's all natural, made with various essential oils like lavender, citrus and eucalyptus, and it really is the most magical product out there (I'm not kidding!). I just took a pail, squirted some soap in there, added some warm water and then used a white rag to wipe everything down.
Even though it is all natural, it costs pretty much the same as the other (more toxic) commercial cleaners and you can use it for practically everything. Here's the website: http://www.drbronner.com/