router woes/ lag spikes

i havent played enemy territory forever and i dunno if and when i will get a new rig so i decided to try playing on my not fried computer. It is updated to vista sp1. Using a linksys router, and a netgear wireless adapter which are both on most of the day. Linksys always keeps cool but the adapter can get quite warm at times to the extent that i unplug it to let it cool.
it gets its signal from a router but the connection is constantly jumpy, it would lag and then go back to normal repeatly when i tried to play. always at random to. i would have a couple seconds to a few minutes before a spike.
Im currently getting cable internet(comcast). Has been an isssue ever since i got this computer but never bothered me since i dont really play games on it.

no expert at internet connection/packets and such. sorry.

if you need more info just tell me what and where to find it and i will try to fill you in.

Oh and by the way, i don't have a host computer or a main one connected directly to the cable modem. Dunno if that helps.

is there anyway i can make my connection stable?