How do you get the smell of cat urine out of furniture, such as a living room sofa?

My female cat who is approximately one year old has been peeing on what seems like everything. She peed on an old sofa that we had not too long ago, so we got rid of the entire sofa because it smelled so awful. We then bought a new sofa that is a suede material. Not long after getting this sofa I found that she peed all over both seats on it. This has become very frustrating and embarring when I have company over. I tried MANY different kinds of little pet sprays that they sell at any pet store, but no luck. I also rented a rug shampooer with a hose attachment and got solution to use for the sofa for pet odors, after shampooing twice, nothing has happened. THEN i decided to use nature's miracle spray and nothing happened, still smells bad. I feel like the odor is everywhere and I keep finding new places. I've taken her to the vet and got her checked for a urinary tract infection, and it wasn't that, just a simple behavior problem. Please, someone help!