HeyThere:
... it was during this part of the convo that she said the stuff about blood giving the recipient the addictions of the person the blood came from.
Apart from her statement being complete nonsense (as others have already pointed out), when the theological or scriptural arguments against blood transfusions fall apart, JWs (and I did it myself with people) would switch to medical arguments against blood transfusions - the health risks, etc.
The medical argument is irrelevant. Blood transfusions could be completely risk free and healthy, but if the theological argument stands up, JWs still wouldn't be able to have one no matter how wonderful they are because God's prohibition would be clear. Seeing as the theological arguments are full of holes and inconsistencies, they have to use real, exaggerated or bogus horror stories about transfusion health risks to bolster their case. Don't let your JW do that. Keep doing what you are doing in bringing her back to the scriptural arguments.