Is there anything I need to know? Do I need to tell them I'm nursing? I'm taking in between 1700-1800 calories a day without working out, will I need to up my calories?

Anything else I need to know feel free to post it!

Depends. Are you talking about the Curves diet, or just the Curves workout? I don't know what their diet consists of. But if it's the workout, it has nothing to do with nursing. You can exercise all you like with nursing. 1700-1800 cals a day sounds good for nursing.