1) If you're talking about IIMs I'd say chances are zero with that percentile, sorry. I had a 93.9 percentile three years back and yet I got no call.
2) Depends. If you think you can get your percentile to leap to the 95+ scores, then go for it. Or if you want to use your CAT scores for other Business Schools. Otherwise I'd think its a year waste if you are not doing anything meanwhile.
3) In India, its about the same. If you get it from a University, it is an MBA degree that you get. If it is from Institutes like IIM, XLRI, etc., you'll get a PGDBM.
And just one thing. CAT exams aren't the end of the road, don't take the dissapointment too hard. The syllabus of Indian B-schools are designed to make you an MBA or PGDBM holder, not a manager. Ultimately it is the person that you are, that is going to make the difference whether you are successful in life or not. This is from personal experience. Without an MBA from IIM, you aren't missing any big thing in life, however hyped up media wants it to be.