I don't agree. As long as you don't have to have everything running on absolute maximum for ages, you can keep a GPU for about two years. That's what I do - run games at high for as long as they're playable, then drop the settings bit by bit. Plus, turning off things like AA/AF can make a massive difference to your frame-rate and most games look pretty good even on low these days. However, he does need a new GPU, because that one is hopelessly out of date - it's probably PS2 era, or thereabouts. My card will probably set you back less than ?100 now - I got it for ?125 three months or so ago. Just make sure it works with your motherboard.
And never get a high range card when it's just come out: there are never games around that can take advantage of it and by the time such games do come out, the price would've dropped. The last card I bought was an X1950XT for ?115 - six months earlier, the same card was ?300+. So just lower your standards a touch and there's no reason why you can't keep a GPU for quite a long time. What are your complete specs, by the way?