You need about 100 rep points for 2 green bars.
0-99 = 1 bar
100 = 2 bars
200 = 3 bars
300 =4 bars
400 = 5 bars
500 = 6 bars
700 = 7 bars
900 = 8 bars
1100 = 9 bars
1300 = 10 bars
1500 = 11 bars
As for how long that might take? Well, if you make decent threads and post good responses often, then it shouldn't take very long at all.
