Hope you don't mind a newbie question here!

But does it still make sense to buy a Radeon 7850 for mining?
How long does it currently take for you guys to mine 1BTC with such a 7850?
Since I'm totally new to mining I run a test with my gforce at about 80Mhs and didn't make even 1 satoshi in days. So when I multiply times 3.5, which is about the performance of a 7850 (280Mhs), whats the gain? It still would take months to make 1BTC. Am I wrong?