Graphics card broke, is it worth getting a stop-gap card?

I've had my faithful Athlon 2600+ a couple of years now and she's been starting to struggle a bit with new games so I've been toying with the idea of getting a new system at some point in the future. The decision has been forced on me early though, since my trusty 5700 Ultra decided it had had enough yesterday and gave up the ghost.

I'm now left with a couple of choices of what to do for a gaming rig.

1. Buy a 6600GT for 120, making the system a 2600+ 1.5gig 333mhz RAM 6600GT. I'm hoping this will give me something of a performance boost over the old 5700 Ultra, enough to run current games on medium settings, and also to run DDO reasonably well. Then in about a year or so when even thinking about running new games would give it a heart attack I might buy a new system to run more modern games.

2. Buy a cheap ass card for it and sell it on as an Internet browsing PC. Then buy up the components for a new system. I'm looking at an Athlon 3800 dual core with 2gig and a 7800GT which looks like it should cost about a grand all told, though I may be able to shave that a little by shopping about. This way I'd be able to run any games I want on high, which would be nice and also run upcoming games too. The downside of course is that it costs a grand and DDO aside I'm not sure when the next game I'll have to have will come out.

What do you think? Would a 6600GT adequately last me a few more months? And how long would it be before the new one is as rusty as my current rig? Thanks for any replies