Headliners that are hung on bows like your Camaro are basically installed the same. Find the center of the headliner front and rear, the center of the car front and rear, and mark it. Hang the headliner, stretch front to rear first making sure to keep the headliner centered, and then stretch side to side. Attach around the perimeter (some attach with tacks or staples, some attach with glue) and trim off the excess. www.stockinteriors.com
and a dozen other places have your headliner for under $100. Check the knowledge base for tips on installation. This is not a hard job in a smaller car like yours. Just remember one basic thing......do not cut anything off until you are absolutely sure. Even if you screw it up the first time, for another $100 you are back in business and will have the satisfaction of doing it yourself. Good luck.