To be honest,  its difficult to predict the actual rank or JEE advanced qualifying marks. Neverthless, you may calculate your expected rank by this formula

A percentile is the no.of Candidates who scored better than you in the exam. Going by that, to calculate your JEE percentille, we should use the formula 100 - your total percentile score. Now 869010 Candidates appeared for Jan exam. Going by that, your rank formula  is (100 - your total score) X 869010 /100. Your rank can be predicted by using the formula, (100-your total percentile)*869010/100. In your case, your approximate rank would be 185099. Let's say the number of candidates for April exam increased to 12,00,000 then your final rank shall be (100 - your total score) X 12,00,000/100

At this point in time, it is difficult to predict the JEE Advanced qualifying marks but 85 percentile and above should be an ideal score. May be you should consider the option of appearing for April session of JEE Mains.