We were unable to locate a California legal aftermarket catalytic converter for your Suzuki Vitara. Your option is to purchase an original exhaust manifold and catalytic converter from the dealer. You may also contact the State's Smog Check Parts locator by calling 800–622–7733.
In the mean time you may ask the DMV for an extension; although recently the greatest extension they have been giving has been for 30 days. Not sure if this will help you out. There is a $50.00 fee involved for the extension as well. Visit a local DMV branch. It is recommended to make an appointment first as the average wait time now is 1.5 hours.