How to revoke a property once gifted

Dear sir, i am ms. uma bhattacharya,89 yrs old, unmarried, single,retired principal and a president awardee.In the yr 1969 I got a house made out of my own funds& ever since then had been staying there.I had 2 brothers both younger to me.In the yr 2008, my youngest brother & his wife both pensioners requested for shelter & and i offered them accommodation at my home, they offered to look after me for ever.Since he was my own brother i trusted them.I also bore their all the expenses of household including their food and welfare.In 2009, i fell down and had an head injury. frequently used to have headache &was under frequent medication.In Feb 2010, my other brother died. In april 2010, my younger brother & his wife took advantage of my poor health & in connivance with his only daughter and son in law, got a will of my property in their name of my brother. In 2011, with the ulterior motive of grabbing my house convinced me to add another floor on my house as this will help me add income