I take it your wheel is not leather? Why not just find a wheel you like and install it. Much better than a cover, I know Sonic and Camaro wheels fit. I would also think that Malibu/Impala wheels would also fit. Just look at other Holden vehicles and see what strikes your fancy. It is done with just a few simple tools. I am actually going out after I finish here on CruzeTalk to change mine to a Camaro Hot Wheels one with red stitching.
How to remove and replace your steering wheel
Mine's done: How-To: Add a Working Paddle Shift Steering Wheel
How to remove and replace your steering wheel
Mine's done: How-To: Add a Working Paddle Shift Steering Wheel