How do I retrieve music from old iPhone?

I have an old iPhone that has a bunch of music, pictures, etc. on it that I want to pull off it and put onto my new Macbook Pro. My old Macbook Pro had all of it on it, but got stolen and I had NO backup! UGH! So, I tried syncing the old iphone to this new Macbook Pro, that doesn't have anything on it yet, to try and get the music and other stuff off it; but I got a message saying that if I sync it with the new computer, all the media on the old iphone will be replaced! I don't want to lose it, I want to retrieve it! There's GOT to be a way! Can someone help me out?

Basically, I just want to download all the content off this old iPhone onto the laptop so I have SOME music and some of the pictures I lost from when my laptop was stolen.