^^^ That's the DVD, Ummmm, not the Amazon Prime streaming service.
To check whether any film is available via Amazon Prime go to the Amazon home page and change 'All' (to the left of the search field) to 'Amazon Video'. Juana La Loca isn't listed there.
As far as I can tell, the film has only be released on DVD with English subtitles for the US market. So you'd need a multi-region DVD player to watch it (after buying it from Amazon USA for $15).