Copying all pictures from iPhone to PC

I'm getting an iPhone 5 in a month and I'd like to copy the 5,700 pictures in my camera roll onto my computer. When I plug in my phone, iTunes opens but the autoplay dialogue box doesn't show up and the phone is not recognized under "My Computer". I tried plugging in and unplugging my phone with a few different cords. I've looked on other discussions but none of that has remotely worked. I don't want to lose all these pictures nor have to select and send each one through email or bump to my iPod. How can I fix this so the autoplay box shows up or another easy way to get all of these pictures onto my computer?