Property dispute

I and my father had bought a property around 30 years back. The property is on name of my father who has died. I had paid installments for the property by cheque from my account. My money was involved in purchase of plot and building the house

My father has not left any will and now my sister is asking for share in property. My mother is alive and lives with me.

Can my sister claim any right on this property. Should we fight a legal case or it won't help ?