It really depends on what the rest of your app looks like.
How much clinical volunteering have you done? How much non clinical volunteering have you done? How many hrs of shadowing? How much research have you done? Any publications? Abstract presentation at a conference?
Sounds like you will have a good amount of research if you get the clinical research job. Most importantly you need to do well on the MCAT. Studying for a year is probably to much time. Very likely you will forget stuff by the time of test date, and you'd probably run out of practice questions by then. The MCAT should take 2-3 months to study (~1 month for content review, ~ 2 months doing practice questions and timed full-length practice exams) if you have done college properly and actually learned the material in your premed courses.