What type of school did you go to? I realize that the score you got is not good, but there will be some give since you are a domestic student and a little more give if you went to a smaller liberal arts school. My professors tell me that students from those schools are expected to do worse, and hence, that gives a little lee way. I'm about in the same boat as you (32%) and I'm still shooting big. You have a first authorship, which is going to look fairly good, and your GPA isn't bad. If you get good recs that will help. I personally figure if I don't get in, I can do research for the next year and study to retake the GRE's. Better to go someplace I want to go than one I don't.
I think we stack up about the same, so if you want to check out where I am applying, and some info that will be on my apps:
http://www.applycorner.com/graduatescho ... p?uid=4021