If you are planning to use 12 hours outside the airport you need to get a transit visa. Visa on arrival is done in Malaysia airport. The fee is RM 200 that is near to 4,000rs. If you are planning to spend time in the airport here is what you could do
-Take a walk
-Try cuisine in the airport -Shop to your hearts content
-There is a rainforest in the airport to spend time
-Sleep on the lounge sofa -Find a feet massager and get your foot thoroughly massaged. If you are planning to spend outside the airport here are things to do in Malaysia
Visit twin towers
Try half day trip to Bath caves
Spend great cool time in Genting
Get into petronas tower
Step into little India to try Indian cuisine and window shop.