You’ll need to get some sort of router to handle the routing from your 172.16.1.0 subnet to the public IP address.
You don’t have to, but most people put the router as the 172.16.1.1 IP address, so the computer which is using that IP address you’ll want to make 172.16.1.126.
Any home or small business router will do. You can usually get them for ~$100 or so US. You can then configure that router to have one of the public IP addresses, and the private IP address of 172.16.1.1. Most of these routers also support a DHCP server so that you don’t have to assign a static IP to each computer.