Pradip, its hard to give advice with so little facts.
(1) Did you marry in India according to HinduMarriage Act? Do you have enough proof of this marriage such as photos, priest certificate, court documents etc.?
You are saying "she decided to marry you" Does that mean ... She didnot marry you . If she didnot marry you OFFICIALLY...sorry..you can not do anything. Just forget her and find a good Indian girl to marry. There are many very lovely Indian women who are loyal and caring.
Once again, If the NRI girl DIDNOT marry you LEGALLY...you have NO CASE as You two have never married.
Remember that in USA ,the laws are very different when it comes to divorce. Many states here have what is callled "NO Fault Divorce" which means there is no need to give any reason why someone wants divorce and diivorce doesnot need permission of both husband and wife. If one partner wants divorce. thats considered fine and divorce is granted by courts in very short time.