Use this API instead core_course_get_courses, where you can fetch all course information. the logic is like
core_course_get_courses. (API function name defines its path)
1. Core : moodle or your root folder
2. Course : course folder
3. get_courses : search for function get_courses() within the "course/externallib.php"
4. if desired fields are not fetched, the alter query (include course price , start date, end date )
5. pass the parameters in get_courses_returns()