First of all, don't worry about your undergraduate GPA. Graduate programs require you take the GMAT or the GRE, and if you ace that test your undergrad GPA can be mitigated. Besides, the distance from 2.8 to 3.0 is pretty short...don't eliminate yourself because you're interpreting the requirements too literally.
I was a part time adjunct professor for several years in a graduate program in a NY based university and I worked with the admissions office, so I have some knowledge in this area. If you want to go to graduate school, you can.
You don't necessarily need a PhD. You certainly don't need one to get an entry level job as a sociologist, and if you do need one for ultimate career advancement you can always get one on your employer's dime.
If what you're looking to do is move into data analysis, however, what you really need to do is get some credentials in statistics. Sociology and statistics are highly correlated disciplines, and you can have an extremely rewarding and successful career as a professional statistician working with sociologists. Statistics is also a natural for someone who makes his living in IT...you're firing the same brain cells to be good at both.
Seems to me you have two choices, both of which will take some time. One...go back to school and get an M.S. in statistics. Never a bad idea, and something you can have a lot of control over. Two...get onto a project at work that's heavily stat oriented, then learn baby learn. If your current employer has no such opportunity, capitalize on your IT credentials to get a new job with another employer who does do that kind of work. Either way you'll come out the other side with the chops you'll need to do what you want to do.
BTW, don't hold your nose when you say the word "manager". You're mostly right in that the older you get the better your employment prospects if you're at the management level. If that's not what you want to do, then you can do what a lot of other folks have done...spend the first half of your career as an IT professional who works with other professionals in a cross-section of disciplines, then use that to carve out a plan for the second half of your career. Maybe it's as a manager, maybe as a sociologist or an analyst, or maybe as a carpenter. Whatever turns you on.