My ps3 wont connect with my router?

Ok I got internet today. The guy said I needed a linksys router because it was good for gaming and more compatable with their company. So I went out and bought the cisco linksys router. I ddont have a computer just 2 ps3s. He hooked the modem cable to the ps3 and I was able to get on the internet. But I want my bf to play as well with my other ps3. So I hooked my modem into my new router and the router had the internet light on, my ps3s detected it and the ip address succeeded but the internet failed, WTF??? So I tried hardwiring it, modem plugged into my router and plugged the ethernet cords from my ps3s to the router.... still no internet. WTF???? I don't understand it? The router came with a set up disc, do I need to get someones laptop to set up my router? I'm just lost! I don't understand it! My router says it has the internet my ps3s detedt it but can't get the internet! HELP