Help with new kitten?

Today my sister brought me a new kitten, a long haired little girl
I'm guessing the little one is around 5-8 weeks, but she seems fairly young (still teething). The problem is, after being with my sister for a week, baby kitty's breath smells foul like bad wet food, and she has dark brown runny diarrhea which also smells like bad kitten food (and feces, of course.) She's one odiferous little bundle of fur! Her eyes are crusty as well, and I can't get the crust off with water because I don't want to rub too hard! Anyone have any advice that could help me out?

I appreciate it!!

Yes, please get the kitten to a vet now - there may be multiple things wrong and at that age she might not survive.

She needs to see the Vet fast.

Until you get to the vet, I'd start with a good quality kitten food, preferably soft.