I need a simple answer for a router question

[Shroomster]

I have what apparently is a pretty generic router Linksys WRT54G2.

FACTS:

I use it primarily for my PS3.

The PS3 is connected wirelessly to the router.

The signal is between 60-80% usually with spikes in either direction.

Signal passes through maybe 2-3 walls; about 12-20' from the PS3 in a direct line.

I have read online the PS3 has a g card in it.

Would anything change as far as gameplay/response is concerned if I upgraded to an 'N' router?

I played two games of deathmatch in Mw2 tonight and total between the two was 3 kills and 28 deaths. it seemed like the gameplay was choppy (not iceskating) but like you could see a refresh rate kind of thing happening to the screen. the signal status on the game said i had 4 of 4 bars....
I don't know if it's the router, my ISP, or if I just suck that bad anymore lol.....