I've use the following products and remedies. Woolite Heavy Traffic foam carpet cleaner! Bissell pet pre-treatment spray, Bissell advanced pet odor removal, Bissell spring clean, vinegar/baking soda/peroxide/ lemon.

The urine has gotten into the pad and the sub flooring. Nothing will truly remove that odor other than replacing the carpet and pad and treating the sub flooring (you may even have to replace some of it if it's really badly soaked).

^^^^^ I agree with Anglophilia. I believe you can use an odor blocking paint on the sub floor, but depending on what it looks like once the carpet and pad are up, a safe approach is to replace the sub-floor.

There are odor remediation companies that you can hire, or at least bring in for a consultation. They might be able to get rid of the odor without replacing the carpet.