Cegep/University Dilemma

[hobbyjogger]

I am a 2nd year CEGEP student at Marianopolis in Commerce (Social Science). However, I don't necessarily like business and I would rather study something in the Life Sciences group in University, which requires a Science DEC to be admitted. I tried to switch into Health Science at Marianopolis but I wasn't accepted as my Secondary 5 Chem and Physics grades weren't high enough (mid-high 70s). I've matured a lot since high school, and my CEGEP grades (In Commerce) are much better.  (89%/33 Côte R). I'm asking for advice on the best way to get into these University programs that have Science classes as prerequisites. Should I 

1) Apply to a different CEGEP in Sciences to get the required classes. If so, where should I apply to maximize my chances of getting accepted ? I can do both French and English. 

2) Enter a "pathways" Cegep program, where I can retake my Chem and Physics classes to improve my grades before applying to a Science DEC program.

3) Apply to University in an Arts program and take the required science classes in my first year before attempting to switch - I was told this was possible at Concordia for Engineering, but I don't know if I can do it at other schools like McGill or UdeM

or any other option that you would suggest

If anyone has been in the same situation  I would greatly appreciate it if you told me what you ended up doing, or gave me any advice.