Damn Router!Follow

Alright, I have a linksys wireless router 2.4GHz that is hooked up directly to my cable modem. This router connects my computer and my ps2 to the internet. I play FFXI on my ps2 while my brother playes on my computer. I also have 2 other computers on the other side of my house that are connected to the internet using a wireless adapter. I never have any problems trying to play if I am on the internet using my computer which is directly hooked up to my modem, but I have problems if someone in my house tries to use one of the other computers. I always get disconnected when someone else tries to access the internet. My brother and I can even play FFXI at the same time and I will not get any connection issues. Is there anything I can do to prevent getting disconnected whenever someone tries to get on the internet on one of the other computers? It is very frusterating (sp?) because my dad is a big computer guy and hes always online preventing me from getting a good 2 hours in without getting d/ced. Would a better router with more GHz help with the problem? Thanks in advance for any input!