It's possible that the problem you're having is resident in your home. It's possible that the actual smoke smell can get into the home and remain there for a long time. I'm afraid that the best you can really do is to replace the carpet and re-paint all the walls. This is what I had to end up doing to my home because the previous owners were smokers and had pets in their home that they left over many days. As you can guess, the area was quite a mess.
Another thing that has helped out my household quite a bit with taking care of this problem are air purifiers. Particularly the Polarized Media Filters. I haven't really heard of a better type, and I've researched them quite a bit to get rid of how bad the air was in my house. The best place for those are on
www.airlifeone.com, for price anyway. They've got good information on what they do too.
The best kind of paints can be found at most hardwares, I'd suggest an odor blocker type of paint. This is really all I can think of for what we did to our home.