I glued on a piece of plastic to hold the rubber standoff that was broken off and managed to find 4 more of the retainer clips at Pull A Part. They even let me have them for free!
I got it on today but it isn't sitting flush against the window at the passenger spray nozzle. I pulled it off and on several times checking the alignment but everything is going together as it should. I'm still not pleased with the quality but considering I got the cowl vent and the retainer clips for free I can't complain too much.