Help with my xbox live connection?

Okay so i have a wireless router with 3 computers and my xbox hooked up to it. we get a wireless internet signal through a tower. Kinda like satellite internet i guess... Everything is hard wired to the router including the xbox. But one computer uses the wireless. I have no problems using the internet on the computers but when i go onto xbox live i play halo 3. It plays fine a lot of the time but probably at least once a match, for a minute or two, it goes to the score screen and says selecting new host (like when someone quits the mach or has a bad connection). Then after a minute or so i come back to life dead like the game continued but i had no connection. I don't know why this happens because it shows i have a great connection. Do you think its possible that the internet just cant send data out fast enough? Or possibly that i'm not using a good enough router for my networking? i'm hoping its the router so im buying a D-Link DGL-4500. I heard its a very good router. If you might have an idea of what the issue might be please help! Anything would help at this point.