not going to sugar coat anything. i think you're in trouble. i think taking it in three months and applying for this application cycle is too late. i say.. re-apply next yr, but study way harder for the DAT.
an 18/20/16 is quite low considering your gpa is below avg also. if i were you, i'd retake. aim for 20+aa and 19+pat. that will improve your chances given your gpa.
just out of curiosity, is english your second language?