Actually, what you have appears to be a portulacaria afra, sometimes called a baby jade or elephant bush. Mine have lost their leaves too, but they should grow once again when the days grow longer and there is more sun and warmth. In California, I am told they grow this as a hedge!
We opwn that plant. We had problems with over-watering. We used to water it as often as our other house plants and it would not like it. We ended up replanting it with a 50/50 mixture of sand and soil and now its growing great. I am still not sure what the name of the plant is. Good luck.. KG moderator's note: removed website link, see point 1.1 of usage rules
