Router

Go to the linksys website

http://www.linksys.com

Then look under support then drivers.
http://www.linksys.com/download/default.asp

Theres the link just click on Firmware.
Do make sure I have the right model number for you though. I selected the Linksys BEFSR 41 Etherfast router with 4 port switch. Which should be yours.

Also make sure you change the default password to the router from admin to something else. lol