unlock phone if the screen disconnected

I dropped my iphone and the screen not only cracked but completely disconnected, it still charges and plays music if I press play with the apple headphones but I have very important photos and voice recordings on there that haven't been backed up due to me just getting a new computer, when I plug it in to my laptop it connects to itunes but it wont back up because I have a passcode on it. how am I supposed to unlock it if the screen doesn't work. I cant put it in DFU mode because I'll loose everything, apple is replacing the phone which is awesome but I need my photos and voice memos off my old one. I have no idea what to do. please help!!!