Property bought in joint name of me and my wife who is a foreigner national

My wife is a foreign national and hold a PIO card and India Pan card as well. I am an Indian national. She was In India posted as diplomat for five years and had her saving bank accounts in India which diplomats can have. She is not liable to file Indian tax return on her salary. She used to transfer money to my Indian saving bank account from her account. Source of money in her account was remittance from her salary in from her own country. I spent some money on every day expenditure and we bought a property in our joint name in India, the money was paid to builder from my bank account as well as her diplomatic saving bank account in which there was no Pan card updation. But the money earnt was hers. Registration of property has been done now in joint name of both with pan card of both. 1. Now once we sell the property, how is the capital gain liability on us? 2. Out of the money she transfered to my account, I paid to my father for a plot in his name, as it was govt allotment in his name and he dint have money to pay, the registration of property is not yet done. is it legally right to buy property in my father name and money was paid from my account online.