I thought it was an advert for a Renault Clio but someone had parked a van instead :-)
(sorry, I'll keep my eye on the birds instead).
You can get routers which lets you have set one port/IP address which is intended as a DMZ (demilitarised zone) and is not covered by its firewall.
Your other PCs will benefit from the firewalls protection and still share the internet connection.
Most routers will also enable you to attach a switch to one of its Ethernet ports.
The pain of setting up routers can also be alleviated by forumites :-)