am I doing enough to lose weight?

I go to the gym six days a week. I do cardivascular on the cross trainer between 30-45 minutes, intensity increases each week, and afterwards I swim about four laps but if I am not swimming I just use the cross trainer. I am planning on booking aerobic classes and legs, bums and tums (or do it at home using Jillian Michaels workout dvd) but is this enough to lose 2lb a week and I am also eating healthy! Cut down on my sugar and carb intake and increased protein and iron.