Hi,
Since the land was bought 30 years back, you will need to get the cost ascertained by a registered valuer as on 01.04.2001. You will get indexation benefit on the same and then you can compute the capital gains on the same. You will need to pay capital gains tax on the same. However you can save the taxes by either reinvesting the entire sale proceeds in a residential property within 2 years of the sale of the land or you can also invest in capital gain bonds. However, since you would need a steady Income, my suggestion would be to pay long terms capital gains tax and reinvest the remaining money which can be used to meet your monthly expenses. Post paying taxes, you can gift the money to your wife and there will be no tax implication there.
Regards,
Nikhil.