If your existing equipment cannot be upgraded, you might have to purchase IPv6-ready equipment. Check the manufacturers' documentation for any equipment-specific procedures you might have to perform to support IPv6.
Certain IPv4 routers cannot be upgraded for IPv6 support. If this situation applies to your topology, physically wire an IPv6 router next to the IPv4 router. Then, you can tunnel from the IPv6 router over the IPv4 router. For tasks for configuring tunnels, refer to Tasks for Configuring Tunnels for IPv6 Support (Task Map).