How can you get dog pee smell out of the house and carpets?

i have a dog and she is 6 and i also need tips on how to train her. it is just becoming a issue and the house smells and we are going to be rentting a house so if we cant train her we will have to get rid of her. its sad!! so any tips on housebreaking a six yr. old dog and how to get pee out of the carpets?!?!?!?!?!?!