I've fallen behind a bit in the academic world, maybe I'm wrong to think the Caribbean will "fix" me. Will they except someone into a DO program from a halfway decent US school?
Fixing your grades while in the US is the way to do it - going to the Caribbean to "fix" only complicates matters - either way, your transcript from all your undergraduate studies must be submitted ... and if you happen to do well academically in the Caribbean, the question remains - "well, it was the caribbean, not a US program"
Remember that there are numerous applicants for each seat in medical school. It's not a check-list where once you completed the task, you get accepted. You are competing against other students, other non-traditionals, etc. Admission committee members are busy and don't want to spend too much time figuring out why you went to the caribbean to finish your undergraduate education, what would you have done if you stayed in the US, can you handle the academics of medical school, etc. It will be easier to toss your application aside and look at the next application.
People who pursue premed at St. George are usually trying to get into St. George's medical school
EDIT: And in the end, it's not anonymous strangers on an internet bulletin board that you must answer these questions to, but medical school admission committee (if they even get to read your personal statement)