The Hindi course has really to less verbs and also vocabulary is not that great. Also it would be wonderful to have some Hindi language stories to improve the language.
I went through a couple of basic Hindi text books and the level of Hindi on Duolingo probably corresponds to second or third grade of the CBSE textbooks.
Stories would be tough as the grammar and vocabulary so far is tiny and Hindi is a complex language with lots of grammar and idioms.
You could probably try CBSE Hindi for 2~3 grade online. The stories aren't bad either and you'll find plenty of sites with explanations.