Sorry Saurabh, we don't understand your question properly. However, Audi Q3 comes in two diesel variants and one petrol variant. If you are asking about the comparison of both these models then please visit the link below-
http://www.cardekho.com/compare/audi-q3-and-audi-q3-and-audi-q3.htm
The exact launch is not yet revealed by the company, we would let you know as soon as we get the information. Follow the link to check all the differences between Audi A4 and BMW X1.
http://www.cardekho.com/compare/audi-a4-and-bmw-x1.htm
Audi A3 would be coming only in petrol version. To know more details of the car, please do follow the site: http://www.cardekho.com/carmodels/Audi/Audi_A3