DSL Firewall

I currently have a Linksys befsr81 8 port DSL/Router up and running and have to departments up and running and sharing the internet(no problem). The router is setup to use DHCP with 192.168.1.1 as the router’s IP address. I purchased a Firebox SOHO|tc firewall. I was told it has better internet security. The firebox has a wan connection and 4 ports. Can I use the firebox just as a firewall? Can I use both the linksys and firebox together? DLS to Firebox and Firebox to linksys.