Dropped Packets

I'm looking for some advice by someone with networking experience. I recently had a fiber connection installed. The way that the ISP set up the IP's wasn't friendly to the AirPort Extreme. My solution was to buy a wired router and use the AirPort in bridge mode. Everything works fine except the D-Link wired router I got keeps dropping packets every 10 min. and does so for another 2 or 3 min. I know I have everything setup the way it should be.... I'm just starting to think that it can't handle the amount of traffic from all the machines on my network (I have 5 machines with one of them as my web server). Does that sound like a reasonable conclusion? If so, should I just run out and buy another router or switch? If you think you can help and have other questions about the setup please ask. I'm open to any help I can get. Thanks.