The Miami International University of Art and Design bases admission decisions mainly on your essay and your interview. I also believe that it's open admissions, meaning that if you send in all the right paperwork, and they still have places in their upcoming class, you will get in. A portfolio is not required.
You don't need to send them your SATs, unless your high school GPA isn't okay. If your grades aren't good, they may ask for the SAT to make sure you are capable of college level work.
If you have a portfolio, you could probably get into a stronger art school. Is it Miami that you love, or something else about that school...? if it's not specifically Miami, but you want away from NY, and your grades are okay, then maybe you might like the Savannah College of Art and Design, in Georgia. It has a bit of the vibe of the school you're looking at, but is a stronger art school.
I assume you don't want to stay in NY, and maybe you want warm weather and a funky city (thus the choice of Miami), so you may also want to look at: Art Center College of Design (CA), California College of the Arts, Laguna College of Art (CA), Otis College of Art (CA), and Ringling College of Art (FL), all of which aren't as hard as RISD to get into, but are good, solid art schools.