Intake manifold gasket replacement

I have a 2002 Chevy Venture minivan with 52,000 miles. It is leaking coolant at the intake manifold gasket. Can anyone tell me a ballpark figure on what it would cost to get this repaired? I have also heard that this is a common problem and many people have complained to GM. Does anyone know if GM has agreed to repair this problem under warranty for vehicles that are currently not under the manufacters original warrantly of 3 years/36,000 miles. Thanks