Generally C-Media does not provide drivers. C-Media is used by sound card vendors such as ASUS. You have to get the driver from the sound card vendor.
I had an HT Omega sound card, in an old system, and it used the C-Media chip. But, HT Omega provided the driver.
What C-Media device do you have? I assume it is an add on sound card. There should be some markings on the card to identify the manufacturer or part number.