Figuring that you'll get about 30MH/s from each card and a total of 60MH/s combined, you should get about .5 Bitcoins per week. Of course this depends on a variety of things like mining software used, mining pool being used, and luck. At worse you could run your setup for about 10 to 12 weeks, cash out, and use that money to get a better card to mine with.
Hmm, that's not too bad.
What amount of bitcoins are people getting per week that have banger ATI cards?