Well to answer your last question first, being a "gringo" is most definately NOT a negative. When i went for my interview there I was surprised by the number of mainland US students (gringos) there, so go for it. They do part of the interview in spanish though. The idea is to see if you can communicate and understand spanish somewhat, although you do not have to be fluent at all. The reason for this is that you will be doing your clinical rotations in a mostly spanish speaking population. The good thing is that they understand that not all of us might know spanish, but after two years there believe me you will.
Ponce does have a small town/ city atmosphere, I assure you its quite pleasant. I truly belive Ponce is one of the undiscovered jewels in medical education. Many students go for "name" schools and end up going through 4 miserable years of med school. In many a thread I read about the "cliqueshness" found in many med schools and gunner syndrome that seems to pervade many mainland schools. I found Ponce to be the total opposite. I spoke to med student there and they all said that the small class size and supportive faculty make a HUGE difference there. As for quality, believe it or not Ponce has a slightly ABOVE average pass rate in the usmle, that says a lot, dont you think?
In the match you will find Ponce students accepted into the most competitive residencies, dont believe call them and ask them if they can fax you their match lists for the last few years. Fortunately for most of us, Ponce is not as well known in the US as many pre meds overlook it because its in PR, too bad for them. That means less competition for us when we apply. While many US med schools have 9,000+ applicants in any given year, Ponce has less then a thousand (~900).
I believe Ponce to be one of the best kept secrets in med schools. Just ask some SDN'rs from Ponce, there are quite a few here. If you want PM me and I will give you their nicks so you can contact them.
Try and do something about the GPA. Maybe you can repeat one or two of your first year classes. You will have an "R" in your transcript but it makes a huge difference in your GPA. Other than that, prepare well for the MCAT and you should be ok.