What course should i take up to study Astro-Physics?

Physics is a good start. As are math, computer science, and astronomy courses. There really aren't many jobs in astrophysics if you don't have a PhD in the field, so plan to major in physics, take the other courses I mentioned above, and spend your summers doing research projects to get a feel for what it's like to do research for a living and to get experience for grad school.