I think its ok to lift etc more so in early pregnancy. I was helping my OH move furniture and bring in our flat pack wardrobes at 4 months. I wouldn't do it now though (34 weeks).
I found giving up smoking really easy. When I fancied one I just asked myself would I want my baby breathing this cr@p. Would I leave him in a smoke filled room. Let someone smoke near him etc etc. Seemed to work.
Also I personally think it looks really trashy to see a pregnant woman smoking! I wouldn't and didn't want people looking at me like that.
Good luck with everything, hope all goes well. Good luck with the quitting :o)