I think the hospital experience you will be getting soon will certainly be of benefit on your second application. However, I'm willing to bet that it was your pre-requisite GPA that resulted in you not receiving interviews. Usually, the personal characteristics only become very important during and after your interview. Your GPA and MCAT scores are usually what determine whether you receive an interview.
I think your MCAT score is okay. If you look
into the statistics posted on my web-site, the average
MCAT score of an accepted student at UBC is around 30Q.
Therefore, I think your biggest priority is to raise
the pre-requisite GPA, as your overall GPA, in my
opinion, is fine. You might want to look into redoing those courses at the university in your city.
This dovetails nicely into my third point, namely the difficulty of the school issuing your GPA. I don't doubt that (edited out) is a very difficult school, and that your cohort of class-mates are extremely intelligent, which probably puts you at a disadvantage in the grading scheme.
However, there is no way for a Canadian school to determine what a 3.65
GPA at (edited out) school would be worth when translated into a Canadian
university's terms. Therefore, I recommend that you re-take the courses in
Canada, as presumably, you would excel in them.
This may be the best proof for Canadian medical schools. After all, they are only interested in seeing that you can academically handle the pace of their curriculums, which they apparently weren't convinced by your current transcript. I would really look into the possibility of re-taking the pre-requisite courses that significantly brought down that GPA. If that isn't possible, the other option might be to pursue a graduate degree. Here again, you have the opportunity to show-case your academic credentials.
My gut hunch is that every school you applied to knows that a (edited out) school's undergraduate degree is difficult. However, nobody, including yourself and your admissions advisor, know what a 3.65 GPA would convert to in Canadian terms. As a result, even if your advisor were to write a letter, I'm not sure how great its impact would be. This is the reason for suggesting that you take those pre-requisites over. Show the Canadian med schools that you can handle their courses on its own turf.
I think you'd be able to get high marks redoing your pre-reqs, which, combined with the volunteer experience will give you a well-rounded application.