If you’re very interested in Computer Science, the best strategy for you is to take MSc. Economics/Mathematics/Biology right now, get 8-8.5+ CGPA and take up B.E. Comp Sci.
It’s not hard, really. All you need is hard (and smart) work and sincerity. Also, help from a senior who can provide you with old question papers and tell you what kind of questions are asked in the first year exams will greatly help.