I had the same problem last year moving into a house which had been redecorated (new paint on all the walls), but which still reeked of stale tobacco. It's a bit hard at this time of year becuase you can't leave the doors open all day, but as well as that, I burned oils in every room, sprayed room sprays several times a day in all the rooms (not the aerosol ones in supermarkets; the smaller ones in glass bottles you can get from garden centres, etc) and burnt joss sticks several times a day. After a few weeks the smell had gone completly. It may take longer for you as you can't have the constant fresh air in the daytime too. It may also depend on how many years worth of smoking has been going on there though.
For carpets, bicarbonate of soda 'soaks up' and destroys odours, but you may have to do this several times. Sprinkle the carpets and leave the bicarb of soda for a few hours, then vacuum up.
Keep persevering and your own nice smells should hopefully take over soon.