Well, I dunno what the slope is of your graphed equation. Hopefully you know the slope is change in y/change in x.
Let's say the slope is 2/3.
2 = (2/3)(-3) + b
2 = -2 + b
b = 4
y = (2/3)x + 4 would be the equation of a line parallel to your equation if the slope is 2/3.