Brown beef, onion and garlic in a large skillet; drain. Add tomato sauce, tomato paste, water, salt and oregano; set aside. In a medium bowl, stir together cheeses. Layer 1/3 meat sauce, 1/2 uncooked lasagna noodles (broken to fit slow cooker) and 1/2 cheese mixture in a slow cooker. Repeat layers, finishing with meat sauce. Cover and cook on low setting for 4 to 5 hours.