2003 Chevy Monte Carlo Power Steering Hose

I have a 2003 Monte Carlo. I have replace the hose for my power steering twice on my car. The first time the hose had just blew off and they replace it and that seemed to work great for about a week. I got up started my car and reversed the car (it was really cold outside too) and soon as I turned the wheel the power steering went out. I put power steering fluid in, and it litterally comes out. they replace the hose again and by the time i got home (10 min away) it was out again! What else could be wrong with it, it seems to blow the hose off.