My 8 year old Yorkie seems sick his temp. is low and he discharge blood in his diarrhea

What can I do to raise my 8yr old yorkies temp?

If you are seeing blood he needs to be seen by a vet.. blood means something is bleeding and that needs to be fixed. Also with him having diarrhea he will be losing important vitamins and minerals.
I am sure one of the more knowledgeable will be able to recommend what to feed your dog until you can get to a vet to help him replace some of the missing vitamins and minerals.

How is he otherwise? Any vomiting?
A normal temp. should be 101-102 degrees Fahrenheit. You will need to make sure he stays warm, a towel covered heating pad will work well for this, not too hot though, just good and warm.
Bloody stool could be caused by a few things, only your Vet will be able to tell you for sure.
Intestinal parasites or irritation to the intestinal tract, or could it be that he has eaten something that he shouldn't have (trash or people food for example)
Has his diet changed?
Loads of variables here.
I would suggest a good check over by your Vet in the meantime, if he is drinking, good.
If not, to keep him hydrated you can offer him Pedialyte or a little chicken broth.
Not the fatty, greasy stuff you would fix yourself though, just a good clear commercial broth.
Best Wishes and let us know how he does,