I was in a very similar situation. My verbal and quantitative scores were great, but I was horrified when I received my writing score. It ended up mattering very little. I found out that admissions committees put less weight on the AW score than the other two, which I assume is due to its lack of external validity. I had several professors tell me my GRE scores were fantastic and didn't even mention my low AW score. Only one professor brought up my writing score during an interview, albeit jokingly. He said my personal statement made up for it. Just write a killer personal statement!