Unsure what dog to get? Westie? Lhasa? etc

Hi all,
I'm getting a new dog very soon, and am very unsure what and where to get one. I'm not a first time owner (I had a lhasa in the past who I got from what I later found out to be a pretty unreliable breeder). Now I am getting a new dog I'm torn between what breed, and shelter vs breeder. I would really truly love to rescue a dog, but all the ones I've browsed in my area have either a lot of terriers/jack russels or large staffies which would not work for me. I have some requirements I really need to consider:
1) A fairly small breed (10-25lbs)
2) Affectionate and loving but isn't prone to separation anxiety as I do go to work. Ideally fairly laid back and happy. No aggression or biting.
3) Doesn't need hours and hours walking each day
4) Is reasonably quiet and doesn't bark all the time as I am living with 3 other housemates.
5) Is safe with children
I've been thinking about another lhasa, but also perhaps a white west highland, and any other suggestions people may have?? I don't know if a shelter will have the right breed for me in the next four weeks (my deadline) so it may have to be a breeder, but if so, I would need a slightly older dog (10 months+), not a puppy. I don't know if breeders generally have dogs that old?

So does anyone have any ideas for a great breed to get, and opinions on whether I should go breeder or rescue?

Thanks guys!!