The more protection the better, in my opinon, especially if you're using an "always on" broadband connection, and even more so if you have a static IP. You can set up your router's firewall through the browser interface, usually by opening your web browser and punching in the address of your router (192.168.1.1 is a common router address for subnets).

>>Is it that one needs both hardware & software firewalls?
All you need is a hardware firewall if it's an actual hardware firewall and not a router with firewall support. If you don't have a "real" hardware firewall then a good software firewall to supplement the router firewall is a good idea.