If I understand correctly, what you are looking for is GM P/N 15247797. Please see index 5 in the following link for clarification of the part.
This original OEM grill comes complete with the two side covers. If I'm understanding the part you are needing correctly, I see a couple of options.
You can go to the dealer or go to the two following websites:
Either way I believe it will end up around $130 dollars - including shipping if you purchase on-line.
I am not aware of any alternate grills that would not interfere with the cruise control sensor. But I have not researched that subject - I decided to keep mine original.