FIU's Speech program has a strong bilingual track. I would maybe try to take some college level Spanish classes. This would show that you have a strong interest in working in the Miami area.
I understand your frustration though. I also applied to FIU. I didn't get in either.
I had a 3.5 GPA, CSD undergraduate degree, 12 hours of college level Spanish, and I've worked in another country teaching ENGLISH! I really don't know what else that school is looking for. Good luck though. I knew a girl who got in and she had a 3.79 GPA. Not really anything special other than that. She said her friend had a higher GPA and didn't get in. There is obviously no method to their madness.
Good luck!