Sammy has a pooping in the house problem (we didn't get her until she was 10 months and she wasn't trained so this is a hard habit to break) anyway she always goes at the same time every day - in the morning and around 4:00 - so I just take her out at those times and DO NOT let her back in until she goes. I have to sit there with her and watch her and it's a pain in the winter but it's better than poop on the floor. Once she goes then she can have freedom no problem.
NILIF is awesome and a good way to treat the issues you are having and a good way to teach tricks. Good luck!
(I have to brag about my Loki though, who would never, ever poop in the house and he hasn't since he was like 6 months old. He is so good. He has other issues... but he is still such a good boy
)