I need to amend my last 3 years of state returns, but i did not use turbo tax for state, only federal, how can i do this?

Yes, you can do that.  

To prepare a past year state return you need to purchase the TurboTax program for that year if you prepared your federal return using TurboTax Online:

NOTE:  To prepare a state return within TurboTax you will first need to prepare a federal return as your federal tax information will flow into the needed state forms.
 

If you already have the TurboTax Desktop version for the previous years they include one free state program.  Your free state is available after you update the software (Online menu, Check for Updates), then click on the State Taxes tab and you should see your state.

If your state return is not complex and you feel confident you can use the state forms to prepare and mail. There is no e-file available for prior years as a general rule but you can check your state's website for verification.

• How do I contact my State Department of Revenue?

to file a state amendment, use the same procedure you used to file the original return,

but use the X form not the regular form.