The good news is that these puppies are nearly old enough to be weaned. Raising a 3 week old litter is not nearly as hard as raising newborns, as they don't need fed as often, can begin eating real food and lapping out of a dish and can potty on their own. Between four and five weeks they can be eating much of what they need on their own, providing they are offered the proper things. If possible avoid using commercial formula. This is a good resource for info and has a good recipe:
http://leerburg.com/pdf/bottlefeedingpuppies.pdf
Also if you take these two puppies, resist the urge to keep both of them and educate yourself about "littermate syndrome":
Stan Rawlinson explains the problems of rearing Two Pups from same litter
Raising Siblings