Need to know if i need a better router

Hello,

okay, so first of all i have 2 xboxes, one of them is mine and the other is my bro's and i just want to play gears of war 3 and my bro too but in his xbox and put the webcam on my laptop with my boyfriend cuz i dont have the headset. So when we do this at the same time then everything lags and when i take off the webcam then we still lag ( me and my bro) and when my bro turns off his xbox then it doesn't lag for me, if i put the webcam and i play xbox then i lag. To put it easier, if i play alone without my bro playing and not having the webcam on then it doesn't lag, If me and my bro play at the same time then it lags, and if we both play and i have the webcam on then it lags. Its weird because its only with gears of war 3 because if i play another game and i put the webcam and with my bro playing another game then it doesn't lag at all and i also find it weird cuz my boyfriend does the same thing as me, he plays and he puts the webcam with me and his lil bro plays too and he doesn't lag at all. I have a modem that has 3 megas and my boyfriend has only 1 mega and my router is a TRENDnet wireless N and my boyfriend has a Linksys wireless g and he said that is kind of old... and why doesn't he lags at all? plz i really need this problem to be solved... i cant keep this up cuz i have to play one day and my bro the other and i cant do anything at all so he can play :( Another important thing is that my boyfriend's brother has a wireless adapter for the xbox and my boyfriend has his xbox connected to the router. Me and my bro have both of our xboxes connected to the router... does it has anything to do with that too?