I'm in my last semester of graduation the results come in August, am I eligible for the mba program now? if not, then when should I apply?

Yes, you are eligible to apply for an MBA course. Technically, you need to have completed your graduation, to get admission to an MBA degree. But students in their final year of graduation can appear in MBA entrance examinations. If you are able to score a decent percentile in the entrance, you will get a provisional admission. Your admission will be final, once you complete your graduation with the required aggregate marks. Your provisional admission will be finalized once your graduation results are declared and you submit the relevant proofs. So, if you have a valid MBA entrance score, you can apply for an MBA program.