How big is a lhasa apso and poodle?

We have a Lhasa apso poodle cross. Both of her parents weighed in at well over 10 lbs. She is now 2.5 years old and weighs only 2.2 kilo a little less than 6 lbs. She is smart as whip, very athletic and loves to play. we love her to death. I don't think she will get better. Perhaps she is a runt - but we don't care.