The router and switch route is probably good enough. If you have 6 PCs then you probably already have a switch connecting them together. You just need a cable going from the switch to the router.
The addition of a router connected to a broadband link will give you internet access.
Beware: most broadband routers are really a mix of router and switch and connecting a switch to a switch in theory needs a crossover cable. Many switches handle this automatically, some one have one port assigned for up-linking to another switch. Some have a button that changes between a normal port and an uplink port, some need to be configured.
Some things to note:
how are your PCs getting an IP address. The router will have a DHCP server built in, so if you already have a DHCP server on your LAN then you need to choose which one to use and switch the other one off, you cannot have 2 DHCP servers on the same network.
The router must be on the same IP network as the rest of the PCs. The easiest way to achieve this is to let the router handle the DHCP.
the router will be your default gateway, so you need to configure the PCs with that information, either by using the DHCP server or manually if you are using static addresses.
I do this for a living