It sounds like everything you are doing is exactly on the right track. I would make sure to get plenty of critical care experience and get the book GRE for Dummies. That book saved me!! It will tell you all about the GRE and how to take the test.
As for the CCRN, it just depends on the what the school finds important. I can say for certain, it won't hurt your chances. I know there are many of us out there who are not CCRN and got into CRNA school. Keep up the good work and don't give up!!