I was at a US post office parking lot in Colorado and started backing out of my spot. The other driver started backing out as I was almost completely out of my parking spot. I stopped and honked at her, but she continued to back up. I tried to quickly shift into drive and get back into my parking spot, but got hit. After the accident the other driver said she was reaching for her ringing cell phone and wasn't paying attention to where she was going. She admitted this at the time, but later changed her story, saying it was a mutual crash. She even left a voicemail message at my house asking for an estimate...so she all but admitted hitting me. My insurance company says it's my word against hers, can I sue? Is there anything I can do?