How to save me and my son from my abusive wife.

Hi, I got married in May 2005, have a son of 9 years.We have always stayed seperate from my parents. I have been living under constant fear and mental pressure due to my wifes controlling and bossy behaviour. She always wanted her way in all situations and will never adjust or tolerate the presence of anyone from my family.Eventhough she is an MBA graduate, refuses to go for work. It is with great difficulty I am managing the family expenses, main reason is her never ending demands for money and resources She always demand that I buy food from out and refuses to cook at home. Everytime my parents have come and stayed with us, she has insulted them by refusing to cook or arrange food for them, and also by refusing to talk to them. She always has problems with my friends and relatives and will always create problems whenever a family function happens in my place. She threw a lot of tantraums when we went for my cousins engagement function. Insulting and belittling me in front of my entire family. She refused to come for the marriage function, which happened in the following week also refused to send my son. She never allows my son to be close to my parents.After this function I refused to give in to her. I was not really getting affected by her tantrums. She was very frustrated that her tantrums are not able to put me down and abuse me, She has this habit of stealing money from my wallet. The other day she stole 200 US dollars out of the 600 USD, from my purse. When I caught her red handed, she felt she has to somehow find new ways for the shame she suffered from this incident. I had started a new business four months back, she is wrongfully, without any proof is accusing me of having an affair with my collegue, who is one of the directors of our company. She seems to be on a constant search for ways and means to put me down and belittle me in front of people who respect and admires me. Now she is threatening to ruin my business by coming to my places of work and creating unwanted situations. Already she called 3 of my employees and spoke bad about me. I had a very tough time convincing them about the exact situation and making them continue to work for me. Now she is threatening to do this to all my collegues.She now feels this is the best way for her to continue her abusive , controlling ways.She is constantly threatening me that she will hurt herself and complain to the police that I hurt her. Two days back she took out a shaving blade and started injuring herself. She was not stopping , even me and my son was pleading her to stop. Finally I had to call some neighbours for help and then she stopped the tantraums. I have audio and video proof of this incident. Also I have recorded many instances of her abusive behaviour. All these incidents of mental torture have really put me in a lot of tension. I am now too scared for me and my sons life. I am scared to run away from the house , as I don't know what she might be upto with my son. She is constantly brainwashing my son saying that everything is my fault. He has been at the receiving end of many instances of torture and abuse, so he is too scared of her, so is obeying and agreeing to all her demands.I could not take her for any counselling as she and her family has refused that option also. Since her mother and brother are Pentecostal believers, they say that she needs deliverance from God and not any help from any psychiatrist/psychologist.Her father also had this similar pattern of behaviour, uncontrolled anger for no reason. And in 2010, their parents got separated, as her mother could not take it anymore. I want to get out of this life of uncertainty and constant fear. I want to save my son also. What would be the best possible way?