shes 7 1/2 weeks old. shes a minature so only 3lbs. need answers asap!! help from most experienced

I bring my dog over to my boyfriend’s mom’s house and just the other day I found out that my dog has worm’s. She is worried that her dog’s might get worm’s by smelling my dog’s poop. Just wondering if it is possible.
Yes I brought my dog to the vet and she got treated.

i have two dogs and im pretty sure they both have it since they are always together… they have had all of the symptoms (diarhea, dull coat, little appetite, coughing) I really freak out when my dogs are sick so I want them dewormed immediately. Is it expensive? I know i need to supply stool samples but how much does all of this cost??
btw they have had symptoms for about a wk.