Actually I am sceptical about the chances as most of the MCA courses including the lateral entry ones ask for a regular degree course. Diploma especially distance ones are not given preference. Have you also pursued any other graduation or just the PG Diploma in Computer applications? The reason is chances of MCA after a regular degree with maths or stats has a better chance. If you belong to WB, then JECA is the entrance but the eligibility also asks for a regular degree. I am sorry. I cant find any good colleges and universities including IGNOU which allow distance learning candidates for MCA. I think you should do a regular recognised degree before you can pursue an MCA course.