Was it leukemia or feline aids virus? I beleive both of these can produce anemia. It really depends on whether they respond to the transfusion. I hate to say this but there is a possibility that they are asking you to come in to discuss the prognosis which may not be good at all if the virus...
If you are just washing dogs for a summer job then just get a good slicker brush and a really good tearless hypoallergenic shampoo. You can use anything from a kiddie pool to your own bath tub. Just be sure not to freeze the dogs with cold hose water.
You should always brush out a dog...