I am sorry to hear you are worried about Diamond. My name is Rebecca. I am a veterinarian and will do my best to help.
I am worried that both her problems are related to her not being spayed. The estrogen her ovaries is producing will contribute to the breast cancer growing and spreading. The blood from her vagina might be from a pyometra, an infection of her uterus.
The blood from her vagina could be coming from her bladder, so this might only be a bladder infection, that might get better after a course of antibiotics.
If I could, I would palpater her bladder and uterus with my hands to see if they feel normal. I would look at some of the blood that is coming from her vagina under a microscope, and try to determine if this is a bladder infection, or a pyometra.
If this is a bladder infection, a course of antibiotics might treat it completely. If it is a pyometra, antibiotics alone will not control the infection; it will continue to come back until her uterus is removed by surgery, or sometimes it can be treated with a combination of prostaglandins (cause uterine contractions to expel the infection) and antibiotics. Even with prostaglandins, pyometra tends to come back.
The aggressive breast tumors are very concerning. Often breast tumors get infected, so antibiotics might help some, but only surgery +/- chemo and radiation can treat breast cancer.
At her age, I can understand if you are reluctant to put her through surgery. I would try to determine if she has a pyometra, and if she does, she may need to take antibiotics for the rest of her life.
Let me know what other questions I can help with.