oh hello fellow greener!!! i feel your pain! i am, however, about to start grad school at my top choice school (applied to 2 and got into both) so i feel somewhat qualified to answer this.
i'm likely in a different situation than you because i knew all along i was going to go for a Masters in Social Work, which is a professional degree and not academic, so academics play a slightly backstage role, but here's what i did.
my senior year i went and met with one of the career counselors. we went throught my whole transcript and we made sure, credit-by-interdisciplinary-credit, that i met all the prerequisites for most MSW programs (we used UW as a guide, which is where i'm actually ending up). i saved that piece of paper for 3 years, because then when it was time to apply to schools, i could show that i had x number of credits for y prereq.
when it was time to apply, i called the schools i was applying to and asked what they would like me to do. they both said to fill out the forms as best as i could and in lieu of a GPA calculation, write a letter to include in my app that said i went to evergreen and to please see my transcript for an evaluation of my academic performance. UW gave me this answer right away because they are also a WA state school and thus are very familiar with evergreen. Portland State was a bit harder to figure out; the first person i talked to said, "ummm i know we've done this before, but i can't remember what you're supposed to do. email so and so" and then so and so took a couple days to figure it out and get back to me, but overall no harm no foul.
so in short, my advice would be to meet with a career counselor--mine was very helpful. it would probably be good if you knew where you wanted to apply, but i'm supposing they could probably help you out with that too. and then get in contact with someone in admissions at the schools you're applying to and ask them what they want you to do. if they aren't familiar with evergreen and how it works, have them contact the career center (find out from a career counselor if that's the proper place to direct them to, first). there is no reason that a nontraditional degree from a state school should hinder you from grad school. you just gotta get on the ball!
good luck!!!