You are doing much of the right stuff, and your first few responders give excellent advice. Toddlers change after much repetition and a hundred reminders, and she WILL eventually give up these behaviors, and move on to something else. (Oh, joy!)
The action of over-arm throwing (and, alas, hitting) are developmental and natural at your daughter's age – she's actually making certain body-brain neurological links, and will be doing a lot of these particular motions for the next few months. So she's developmentally programmed to do this "work."
But you can help redirect it, by, as you are already doing, giving her ways to think and talk about her feelings. That is a huge cognitive step forward. Also, empathizing strongly with her feelings while she's angry or frustrated will give her a chance to feel and process while also experiencing your support, and that gives you a chance to move her emotionally to a happier place. Here's how the brilliant Dr. Harvey Karp practices empathy: http://www.youtube.com/watch?v=fJ1428uYs2g&NR=1&a.... .
And it's often possible to "surprise" littles out of a mood by helping her turn throwing into a giggly game. Give her back the thing she threw, or something softer and safer, and give her an appropriate "target" to throw at again. This might be a loop made with your arms, or a box on the floor, or some other suitable and handy target. And take some time to do LOTS of throwing games during the day so she'll get her developmental needs met.