CVA's (Cerebral Vascular Accidents), which strokes fall under, can take many forms and the causes are equally varied. The thing is, the causes each take months, years, or decades to build up enough to cause them, so three days aren't going to make a whole lot of difference.
If the cause is a clot forming (which is the root cause for two types of stroke), then blood thinners could save her life. Most doctors would need to see the patient, but even in the third world, doctors should be trained to deal with that (getting them to care is not something I will debate, however)
If, however, you are travelling back in time. Maybe travelling further back will be more fruitful. Changing her diet a decade in the past will certainly prolong her life, but it would depend on you how to get her to do so.
But that brings me to one key question: why save this life? Surely the harsh reality hasn't evaded you? That people die all the time? Or perhaps even more curiously, what caused the need to save her, when far more influential people would certainly be more deserving?