Default Samsung Galaxy S4 Extended battery and Case

I have purchased the 7500 mah ZeroLemon extended battery for the Galaxy S4. It came with the standard case. I like the battery, however I do not like the case. I am wondering is there a case that I can get for this battery that is about the same size as an Otterbox but not bigger. Or is there any other similar battery that I can get that I can get a similar case. I have also heard of some people doing modifications to their otterbox, but I am not sure how it works. Can you all please give me suggestions? I am particular about the case because I am a female and very small and also have small hands. Thank you.