It was indeed a fabulous speech. I happen to have had to go to a meeting for my job which included a lot of what one might call "good old boy republicans"( a fund raising meeting). There was some conversation among these people - many who could be quoted as saying" it's not my party I'm not watching the convention".
Among that group, those who watched her speech were quite impressed with her, so I would assume that those of her party who were not inclined to vote for Obama could certainly have been swayed by her speech.