I have a Health Insurance policy valied from 04/12/09. Now(04/02/2010) I have stone in my kidney. Can I get insurance coverage for remove this stone.

You need to read your policy to see if it covers you for pre-existing conditions such as this.

If you bought a policy in 09, a kidney stone now is not normally a pre existing condition, unless you have had a history of them and had them previously.

If you don't have a policy NOW, no anything you buy now will not cover it.

Check your policy to see what it covers in terms of surgeries, tests etc. As long as your policy is in force and paid up, then you should have no problems.