since your maid has experience, it will not work by giving her warning letters. If you do not want her, you should be kind to her while finding another maid (I suggest overseas maid although it might takes some time but better and not so 'inch'). When the new maid comes, fire her by giving her one month's payment. Although quite expensive, save you trouble as I have the feeling that your maid will play you if you tell her that you do not want her by giving her one month's notice to leave.
Agree with others. Should terminate the contract with her. See if you can ask the agent to find you a replacement.
There are lots of maids out there who can handle the housework well. Don't worry that you cannot find a good helper.
truly understand how you feel.
don't try tolerate her if her attitude is so bad.
find a new one and once the replacement arrives, kick the present one out of your home, you won't regret.
life is too short! don't waste your energy in dealing with this helper!