One thing that will also help you out immensely is to start looking at what specific areas of I/O you are interested in studying (personnel selection, motivation, leadership, etc...) and make a point of showing a marked interest in them. If you are lucky enough to have an I/O psychologist as faculty at your college (I had the benefit of an ABD from my program of choice in the department who was amazingly helpful) see if you can't get an independent study on an area of I/O with them. Most love the idea of having a student genuinely interested in their field and would be willing to do that for you. Not only would that show interest, but also give them an opportunity to get enough experience with you to write one hell of a letter of recommendation and you have demonstration of interest for your personal statement. Also, look for programs that focus on what you are interested in, including what sort of approach they take to I/O. If you want to be more of a practitioner, for example, make that clear and go for programs that focus on that aspect of the field. The more you can show that your interests fit in well with the program, the more likely they are to ignore a slightly lower GPA. Best of luck to you.