Heartbreak is heartbreak, regardless of age. The nice thing is that her first heartbreak is at a nice, young and resilient age (I love everything Diane said about her son) instead of being in the situation of having had a more serious or intimate relationship.
Fathers and honorary 'dads' can be a big help in times like this for young women. There is a lot of depth to these sorts of father/daughter relationships, and hearing compassion, encouragement and truth ("I was really confused about what I wanted when I was a teenage guy too.") is the kind of empathy that can be helpful to young women in this sort of situation. When a father-figure values his daughter, it speaks volumes.
You can tell her she's 'just learning' relationships, and she might be comforted by this, or it might make her feel like you aren't taking her feelings seriously, so for now, perhaps empathy and comfort (and space, if need be) first, and then some more critical discussion later on, when she's got her feet back under her. And instead of a specific book, keep the discussion ongoing. Reading books or watching tv/movies together, and then talking about what is healthy, what's realistic, and what is just a fairy tale (idealistic, romantic, but ultimately a facade) can help. Just the movie "Grease" has endless topics of discussion, and if that's too risque for her, even the Disney movies or popular Twilight series are good fodder. (I don't know what sorts of media your family allows-- these are just guesses, for movies.) And classic novels-- Anne of Green Gables and the Little House on the Prairie books have something to offer in regard to realistic love pairs; Little Women has loads to work with, and Jane Eyre--oh, that Mr. Rochester... nice in a story, but is that really the kind of person that will make you happy? ;)
It's easy for kids to get caught up in "going with" each other. This can be as simple as just sitting together at lunch or holding hands. Let her know, too, that the next time she likes a boy, her parents would like to meet him. At this age, I had restrictions on 'dating'-- it had to be a group event/outing and it had to be chaperoned. There's still a lot of wiggle room there.
Keep on talking to your daughter, and most important, keep listening. I didn't have that sort of dialogue or openness with my folks, and it made some situations harder. Your daughter is fortunate to have such a loving and caring mom.