PhD programs in Industrial-Organizational Psychology?

Have you also considered something in Health Psychology? I would think with your work experience in public health that might be an edge you would have over other applicants that don't have work experience. Or you might consider a blended program, one that involves aspects of I-O & Health psych, I know I've seen a few of those. I think if you do a thorough search you will find some programs that you match up with. I don't think your age is such a negative factor as you think. It's practical work experience, and it's not like you've been doing something totally unrelated. Plus your GPA looks good and being a member in the APA shows you have maintained an interest in psychology, even though you have been working in public health. Despite your low GRE, there are programs that would accept you with those numbers. I don't know so much about the job prospects in I-O after you graduate, maybe someone else can answer that for you. Good luck!