I have a little longhair black and tan dachshund. She is nine or ten years old, rescued from a puppy mill at age three. She is 8 1/2 lbs and is the sweetest little lap dog there is. She appreciates every meal, every scrap of affection. She is such a perfect companion that I will probably always have a dachshund now that she has spoiled me!!
Regarding size, dachshunds can range from about 7 lbs for a miniature, to 25 lbs or so for a standard size. Look around and see where you can get a miniature dachshund locally. There are good breeders in every state, and of course I recommend rescue dogs. Try http://www.petfinder.com
and type in your zip code and preferred breed.
Good luck and enjoy your new little companion!