It would be worth checking those settings on your isp website since there is some variation from ISP to ISP. The fact that it started when you got the new router however suggests that perhaps the new router cannot cope with some of the demands that you're placing on it. One thing that particularly stresses routers is P2P file sharing since it tends to make lots of simultaneous connections. If you run any P2P software including TV download services (like BBC iplayer in the UK) try shutting them down rebooting the router and seeing if your still getting time outs.
If that helps it might be worth changing the DNS settings on your PC to use OpenDNS or your ISPs DNS servers since the default is to use the inbuilt one of the router and this can cause problems.