Applied math PhD programs - no. of courses to counterbalance low GPA? I’m about to turn 38 and after much research and consideration I have decided that I need to return to school. My goal is to apply to applied math PhD programs and work in industry, ideally working on problems in computational science or fluid dynamics. 

My major (economics and math) GPA from a good public school was around 3.03 and my GPA for my math courses fell at 2.88. Previously I experienced some very serious issues in my life that played its role in this (not an excuse but just an unfortunate fact at the time). 

I’ve reached out to some professors about my background and have been told that my GPA, though not considered the sole factor in determining admission, is a problem. I plan on applying to and enrolling in a post baccalaureate program at an Ivy league college near my home and plan on sitting for the math GRE subject test but I feel like I need to take more courses than I can afford to even be considered for such programs (the courses for the post bac. program are around $6K each). 

I’m prepared to use a good bit of my life savings and working part time to fund this but I would like to learn how I can get a better sense of how many more courses I should take to counterbalance my low GPA.  Would graduate committees be open to giving an unofficial assessment of my background before applying? I don’t plan on applying to the elite schools because I feel that my GPA would knock me out regardless. 

Some background on me:

Since graduating I’ve had varied work experience such as working as a math tutor to working in finance in the last 10 years. I also have a good bit of experience programming and have furthered my education to some extent for what it's worth: passed an online specialization course in R programming that spanned roughly 9 months, picked up a number of financial licenses, and even passed an actuarial exam when I was considering that route. 

I do have course work in calculus, econometrics, ODEs, linear algebra, and an intro to analysis course.

Any thoughts/insights are definitely much appreciated.
I would be surprised if the admissions committee paid that much attention to a number determined so many years ago. First of all the math GRE is extremely difficult and demanding, and if you do well on it people would notice. I would say if a professor looks at your GPA and has some concerns and then turns to your math GRE and sees that you scored 65%, 70%, etc. their fears will be quickly allayed and forgotten. Probably a GPA above 3 would be good but a few recent courses in senior level or beginning graduate level mathematics with an A-B in all of them together with a letter of recommendation from one of the professors who taught the class would be much more influential. There are so many factors that the admissions committee has to balance when trying to decide if a person is cut out for research, it would be silly for them to focus unduly on one thing like GPA.

My one suggestion is that when you mentioned your coursework you mentioned mostly applied courses. The admissions team will likely be composed of analysts, but also algebraists, topologists, logicians, etc. It would not hurt to flesh out your resume with some proof based courses: an introduction to abstract algebra, an advanced linear algebra class with proofs, going beyond intro analysis, things like that.