You can import your camera roll to your computer using your usb cable as explained here: http://support.apple.com/kb/HT4083.
If you're upgrading your phone, I would recommend that you backup your old phone to your computer using iTunes. Restoring an iTunes backup to your new phone will be much faster than restoring an iCloud backup, and possibly more reliable too.
To back it up to iTunes, connect it to your computer, open iTunes, click on the name of your phone in iTunes, then go to the Summary tab of your iTunes sync settings and click Back Up Now. The go to File>Devices>Transfer Purchases.
When setting up your new phone, when given the option, choose Restore from iTunes Backup and restore this backup to your new phone. It will include your camera roll and other data; restoring the backup will will also sync your apps and other iTunes media from your iTunes library to your new phone.