Moving AD and DNS to dissimilar hardware

Due to the fact that our first AD/DNS server was thrown on a Dell PC, I am trying to move it to a more fault tolerant SERVER. The problem with moving AD roles and creating a secondary DNS blah blah blah is that I would have to manually change the DNS IP address on all clients b/c we are using static IPs. Therefore, I am considering doing a backup and restore through NT Backup. One of my concerns is that the “PC” is still online so when I go to do the restore on to the new hardware I will getan IP conflict??? How do I work around this? Also, neither system has a tape drive installed so I would be backing up to file.
Thanks.