It looks like you might get by with some new J-clips. The existing 7mm units are hard to find, so you may have to look around. Make sure to get the ones for plastic. Remove the existing screws and clips. The clips are consider single use, but if you are careful and lucky you can reuse some. You may have to carefully select some alternate locations to fasten it, drill a ⅛" pilot hole, and then drill the bumper cover out to ¼". Then insert the clips and screw together. Also, there are three plastic push rivets in each corner that may be pulled out and need replacing.
2013 MCA Edition-Sterling Grey
Roush body kit - Splitters/hood scoop
Whiteline suspension w/Koni shocks