daschund training

I have a dachsund/chihuahua that I am having similar problems with. I let her out, but she still comes in and goes in the house. She is mostly urinating outside, but still insists on pooping outside. For a while she was at least pooping in front of the door, now she is going where ever she pleases. I know I have read that the chihuahua does not like the cold, rain, etc., but I am not so sure about the dachsund. It's really hard with the mix of breeds to know what to do most of the time, since I don't know which breed could be connected to the problem.