I'm glad you are thinking all this through - adding a puppy to your family is a big step.
Some general thoughts:
First, as Lucy so aptly points out, pure bred puppies from a reputable breeder will not be inexpensive - expect to pay CHF 1000-3000+, depending on the breed, and lineage.
Yes, you might find a 'cheap' puppy from a puppy mill- or as they are now known, battery farmed dogs. But these poor dogs are bred with no thought to health or temperament, and often are very sick, often have extraordinarily high incidences of genetic disorders. They are usually kept in unspeakable conditions, the puppies are not socialized whatsoever - the suffering is horrendous. So eyes open - a pure bred puppy being sold cheaply is probably a battery farmed dog - please don't support this vile trade.
If you go to a breeder, please only go to a reputable, ethical breeder who breeds according to the regulations of an FCI breed club. Do your reasearch into the breed characteristics, with emphasis on temperament and inherited conditions; know what tests are required for the parents, and what additional tests are recommended to be done prior to breeding. Carefully vet the breeder, be sure you meet the mother and whenever possible the father, and be sure you are given a copy of all relevant medical tests. And, be prepared to wait. Most good breeders will want to meet you well before a litter is planned; some have waiting lists of a year or more. Expect to be carefully grilled as to the kind of life you can provide for the pup.
Go to the breed club of the breeds you are interested in; the club will have a 'Zuchtwart' who keeps record of all current and upcoming litters from the club member breeders. That person can best advise you. For a list of SKG breed clubs, see:
http://www.hundeweb.org/docs/SKG/Rasseklubs.pdf
One word of caution given the ages of your children - and please forgive me for stating the obvious if you have already thought this through...
As cute and cuddly as puppies are, they are a LOT of work. They have those needle-sharp little teeth, they do not yet have bite inhibition - you need to teach that. A puppy in house training needs your attention all the time. A puppy and a soon to be crawling baby can be difficult to manage. 'Puppy-proofing' your house before you bring a puppy home is a must. And 'child-proofing' the puppy's space is just as important. A puppy needs a consistent socialization program - do you have time for that now? Having a puppy is almost like having another baby - they need the same amount of attention in the first year. Again, forgive me if you have already thought all this through.
As you probably know, you will be required to take the SKN within the first 12 months of owning the puppy, be sure you research trainers in your area - and it is a good idea to book your course ASAP. You will also have to comply with the new ZH cantonal law, which includes additional training requirements, including puppy classes.
And, just because rescue is my thing... I wouldn't wholly discount the notion of a rescue dog. For instance, the group I volunteer with just rehomed three pure bred sheltie puppies, FCI papers and all; young pups do come into rescue occasionally. Just a thought.
(Although, the rescue I volunteer with does not home puppies to families with children under 5, due to the potential for the kind of problems we see day in and day out. Experience has shown that homing a steady older dog, whose character is known, is often more successful with families with young children. Just another thought to take on board. )
Wishing you and your family - and future furry friend - all the very best.
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