I just wanted to comment on your dd's age. My ds is going to be 8 in 2 months and is just finishing 1st grade! He missed the cut off to go to K when he was 5. I thought it was interesting he is the same age and a whole year behind.
Not dumb b/c I was going to ask the same thing! I wasn't sure if it meant entering 3rd grade ("rising" to 3rd grade, entering 4th grade ("rising" from 3rd grade), or some kind of gifted thing.![]()
She just finished 2nd and is going into 3rd in the fall. I thought it was important to make it clear that she was (rising) into 3rd grade not just having finished 3rd since it's the end of the school year. I guess I was as clear as mud 
The struggle, as you've already discovered, is to find challenging books that are still age appropriate. DD11 wants to read Twilight now - I have told her she can read the first book and maybe the second, but we will have to see about the others.http://www.battleofthebooks.org/4-62011.html
I loved these when I was a kid! Some of the stories are actually scary, so it may depend how your DD handles scary themes, but a lot of them are scary at first but end with a funny twist. Those were always my favorites.If she likes ghost stories, my advanced 10 year old reader loves the "Scary Stories" series. You may want to look over them to see if they are too graphic. My DD has grown up with 3 much older sisters that nothing seems to bother her and she's read them all. I bought them on sale on Amazon for cheap for Christmas. Just look up Scary Stories on Amazon and you should find them.
I just wanted to comment on your dd's age. My ds is going to be 8 in 2 months and is just finishing 1st grade! He missed the cut off to go to K when he was 5. I thought it was interesting he is the same age and a whole year behind.
Anyhoo, he reads at a 3rd grade level and has enjoyed the Geronimo Stilton series. I think they're easy for him, but he finds them funny and if he's reading I'm fine with it.