Normally a dog will bleed for about 3 weeks with it starting out so dark that it is almost black or red and gradually fading to a light tan or pink color. Each dog is different so if a dog bleeds for another week, then I wouldn't worry so much about that as long as there are no other symptoms and it is light. However, if it is bright red blood, she continues bleeding for longer than that, you should have her seen by your vet. If there is a foul odor to the discharge or she has other symptoms such as fever, loss of appetite, vomiting or diarrhea, then you should also have her seen. Bleeding beyond the normal time and other symptoms mentioned could indicate a uterine infection . You can read about this here:
I hope this information is helpful to you.