I also applied twice, as I applied late the first cycle and didn't get accepted. Second time around, I got accepted everywhere I applied with early interviews. I had a c GPA of 3.54 and s GPA of 3.48. I worked as an anesthesia tech, MA, and took post-bacc classes. I had about ~50 anesthesia shadowing hours. I also scored in the 65th percentile for both math and reading on the GRE. I got LORs from my employer, biology professor, and biochem professor.
Honestly what they care about is: a strong GPA/GRE score (to show your academically cut out for the program), a good understanding of the AA profession and how we are integrated into healthcare, and integrity. Not only is it important that you have the drive and knowledge to complete the program along with the passion for the field, but that your patient comes first no matter what.
Overall, it sounds like you are on the right track. Volunteering 2-3 hours per week really isn't much, I would do my best to get at least some sort of hospital based job if you have time. If you have another full time job and can't, then work on getting some shadowing hours and boosting your GPA/GRE. The ADCOMs love people from diverse backgrounds.
Hope this helps!