Taking the CCRN is a good choice, do as many extra curricular "activities" as possible. Let them know all the certifications you have. When I applied I provided a resume with my application that stated all of my work as an ER tech, critical care tech, and nurse tech in various units. Since I had also been a leader in those positions and on committees it showed that I was very outgoing. Be as eager about getting into school as possible, take every opportunity to shadow and meet them on several occasions so they remember who you are, and do well in your interview. You have good enough grades, good GRE scores, and more experience in ICU than the standard 1-2 years. I think what you have is good enough, and since interviews for the three michigan schools
left for the year are generally october-january you don't need to get a job in a different unit. It doesn't hurt to mention if you pick up time in the other units, like occasionally floating to the PICU. If you don't get in this year, then you could strengthen your app by working in another unit. Michigan State has developed a program but they're still looking for a director and really want to open for 2007, so consider looking into this program also, it's about an hour west of most of the other programs.