I spent my first year in college at 18 bombing out and being placed on academic probation. I did end up eventually getting into two nursing programs, but that was after earning a BA in my mid-20s with high-ish GPA and then going back again and earning high grades in the pre-reqs. I would say, though, that it took at least two semesters of all As for my academic record to look sound again. I tend to think that a big turnaround over a period of time will look admirable, but who knows.
Keep in mind, though, that even if a program states a minimum GPA/requires a C+ in pre-reqs/whatever, you will still be competing with students who earned As. Retake the classes, but figure out what you need to do to get Bs or As. Is it organization? Study habits? Do you need a tutor? If you want to get into nursing school, work your butt off and make it happen. :)