Well youll need to give the whole car a goin over as the source of the smell could be under the seats, steering column etc and would of penetrated everythin.
Give the car a full vacuum attach a straw to the vac end to get in the vents
Wet vac all seats, carpets & cloth materials
if you dont have a wet vac then get a good interior cleaner such as autoglym interior cleaner or trade versions super interior cleaner/clean all.
spray Autoglym odour remover on to carpets, mats, seats , inside air vents etc apply every hour untill smell has been removed.
A air con cleaner such as carplan air-con cleaner/ Autoglym Air Con Sanitizer
then finally a good car air freshner sprayed into the vents/car
If you need any more info just let me know.