fix my wireless router

I have wireless internet on the laptop, wired on the computer and I still have NTL with a set top box :D. My friend helped me set it up :D. And it works on Linux too now so I can go on Linux with NTL Internet :D

I bought a router a week ago made by ADDON, my ISP is NTL and my Internet goes through a Digibox. The website I bought it from says that it works with NTL. When I connect it to my computer and connect my laptop wirelessly they can get things from each other but the Internet wont work at all on either of them. If i go to the router page it says it’s getting the IP from the DHCP server, and it’s only ever got it once but lost it again. I have entered the DNS IPs which I got from NTL but it didn’t make a difference. When it did find the IP from the DHCP server it still didn’t connect to the Internet, but I think that might have been because my Internet likes stopping and the light telling me the Internet is on was off. Does anyone have any ideas on what I can do??