There is a product you can get which is produced by Rug Doctor (you can get it anywhere where you can hire the machine) it is called odour eliminator and uses microbes to "eat" the smell.
Works brilliantly - have used it on vomit before (when my daughter thre up all over her bed) and within a day the smell is completely gone. You just spray it on, cover with a damp towel/sheet and let those microbes do their job.
Try it - its about £5 a pop and worth every penny, smells nice too
