First off, welcome to YT!

You will find a lot of great people here and an overwhelming amount of useful information.
If your baby is 5 weeks old right now and you get him in a week or so he will only be 6/7 weeks, am I correct? That is far too young for any small breed dog to be taken away from his momma & litter mates. Most breeders on here will not let their puppies go until they are 12 weeks and have had at least some vaccinations.
I would, and I'm sure many other YTers will, suggest that you ask this breeder to keep your baby until 12 weeks or look elsewhere. Letting a puppy go too soon is red flag for an irresponsible breeder.
I can tell you from experience that bringing home a puppy too soon (@ 8 weeks) can be cause for a lot of health & behavioral issues. We were uneducated when we purchased our first puppy in August and have only now been free of health issues for 2 months now and are still to this day working to correct behavioral issues that would most likely not have been a problem if Jax had not been removed from his mama and litter mates so soon.
I am in no way trying to attack you or make you feel bad but to let you know ahead of time that bringing home a puppy too soon can cause many issues and sometimes even heartbreak.
Try searching around a little bit and you will find LOTS of information about when to bring a puppy home, food, vaccinations and other information you will need.