Forged signatures on agreement to sell

Hi Experts,

A and B are husband & wife and co-owners ( in joint name without mentioning any ratio of share) of a property. A being in dire need of funds , he entered into written agreement to sell of that property with C with forged signatures of B on that document ( Agreement to sell ) , and got the funds from C. After that A committed suiside and B is left alone with that property. 

Now C came with a civil suit into court of permanent injunction as restrain her to deal with that property in any other way except to sell him and to accept the rest of money in regard to that agreement to sell. B astonished badly when she came to know throgh a court notice , regard to above said facts, because she never signed any agreement. The signatures on that agreement to sell are very well forged or managed by her expired husband. 

Now pl suggest except to apear into that case what are criminal and civil attacks are available with B to save her prperty , in any seprate suit or any suit during the proceeding of above said case.