What book is this I can't remember?

Okay so I read it severel years ago and was thinking about it lately. It's about these two sister living in a fantasy world. One sister loves adventure and wants to see the world. The other doesn't want to leave the castle let alone go on an adventure. The adventurous sister gets deathly ill and the pretty girl sister has to search the world to find a cure. She gets kidnapped by a dragon. Almost gets her arm ripped out by an ogre. And she has these shoes that make her jump really far and these gles that let her see things that are far away and through walls. She has a friend that's a guy and his kind are born by some stone getting hit by lightning. I forget the ending but I think she finds the cure. any ideas what book it is?