You could always take the psyc GRE, and if it is not very high you don't have to attach it you your application. I was a psych major, but I only studied for the GRE for about a month, and I scored in the 98th percentile, so I imagine it is worth a try. After establishing a connection with your potential mentors and showing them your expertise in their research, and your good ideas for future projects that you would like to run during grad school, I would ask if they think you had a shot considering your GPA. I would, however, also ask your adviser their opinion. What I found during my interviews was that psychology faculty seem to love science students, so I would imagine it is worth a shot.