How long can you survive if you have breast cancer?

Depends. There are different factors calculated -most importantly the stage of the cancer, the biology/molecular of the cancer, the treatment, response to therapy etc. Other things like age, overall health conditions, your decision are also important and affect on your prognosis and how long you are going to survive. It varies from just a few months to being cured. It is all individualized. D/w your md.
Depends. The large majority of breast cancers today are cured. Especially when the cancer is hormonally responsive, i've seen women survive up to 20 years with metastatic disease.