People do get accepted with only PICU experience. They are exceptions, but it happens. As it stands, your GPA is not competitive at this point. Schools can be different on how they calculate science GPA, doesn't hurt to ask the admissions contact. I would consider the CCRN a must for you so I'm glad to hear you are planning on taking it. A good GRE score (like 310+), even if they don't require it, could help a little given your GPA. It is obviously completely up to you but I think if you took the next year to work in an adult ICU with high acuity, get your CCRN, shadow, and take a couple upper level sciences and get As, you would be a much more competitive candidate. I'm not trying to be a downer but most schools get a ton of applications and will cull by GPA. The problem with where you are now is that to have a real chance of landing an interview, you will have to apply to a lot of schools. That costs money and time and will wear on your references.
I have a friend that was in a similar situation GPA wise. He wanted to go to one school that was about 2.5 hours away. He began taking the open classes of the CRNA program, driving up there twice a week. He got As. He got to meet the faculty. He applied after the first semester and didn't get an interview. He took a couple more classes and was granted an interview and got accepted. That is a tremendous amount of dedication and makes it real hard to say no to a candidate like that.
If this is what you want, don't give up. You CAN do this. It is just going to take some work. Best of luck!