Networking assistance needed, please.

I just got an iMac with OSX for free but the only issue is the network card is dead I have a Speedstream 6520 modem/router that has USB support but I have no idea whats going on with with this Mac it's the first time i have ever used one. I am fairly poficent with PC's but lost on this Mac. so any help with this would be great. I have checked the router and it shows that there is a connection but it's unknown so i think the issue is on the computers end. Please help me and thanks in advance for the help.

p.s. I don't have an airport card (or whatever it's called) and I can't get my hands on one.

Have you got a OS X usb driver for the modem/router?


Alternatively..... Belkin (amongst others) sell a USB-to-LAN adaptor that will act to replace your dead network card.
http://www.belkin.com/uk/support/article/?lid=enu&pid=F5D5055ea&aid=9367&scid=0

If you use one of the these adaptors you can just connect to your router with standard Cat5/6 network cable.