Indian Institute of Fashion and Animation, Bangalore

Yes, you can pursue the Diploma in Interior Design course. Diploma in interior designing is the 1 year diploma level course provided by IIFA Multimedia. IIFA, best interior designing college in Bangalore helps student to create a good interior designing that is aesthetically pleasing. The eligibility criteria of asked course is given below.
Eligibility criteria : Successful completion of 10 + 2 (any stream) Undergraduates and graduates are pleasure to apply

Yes, you can apply.
Students who have passed 10+2 board examination (any stream- Science, Commerce or Arts) are eligible to pursue this course. Minimum marks criteria may exist in the case of some institutes (usually around 50% aggregate marks). Many institutes accept Diploma in Animation holders.

I am sorry to say but you cannot take admission in any proper method since you have less than 60 percent in your boards and the minimum requirement is 60 percent. However you may choose to take lateral entry.

For the exact fee structure, check out the website.