Public IP on Host, Private IP on Guest

Is there a way to set up a guest on my private network with an IP when the host computer uses one of our public IP addresses? I have Ubuntu 12.04 LTS Server w/ Desktop overlay as the host machine which has the public IP address and I have VMware running Ubuntu 12.04 LTS server for Owncloud installation which I need to use a private IP address so it says behind our firewall. Please help!

Thank You