I know a thirteen year old girl who cannot read English very well, and I've been reading to her a lot. She is into romance, a genre I generally cannot stand. I got sick of reading books she chose like The Clique, so I read the Percy Jackson books to her and she loved them. She also liked Gregor the Overlander series. Anything else you can recommend based off those - you know, adventure type fifth grader level books?
Try Rick Riordan's other series, (Heroes of Olympus and The Kane Chronicles.)
The Artemis Fowl books are good :P
Try The Hunger Games. They are a little bit more advanced, I think, but they are by the same aurthor as the Gregor books.
Series of unfortunate events. Thats all I can think of. I read bove my grade level so I don't know many grade 5 books.
Try Inkheart and other books by Cornelia Funke, The Rangers Apprentice series.
Try Pendragon by DJ Machale. if she likes Percy Jackson, she'll love it!
Poison, The kingdom keepers, and...maybe LOTR?