exterior door moulding driving me crazy

[chilton2001]

k i have a 2004 pontaic sunfire 2dr and the little side moulding or trim piece whatever you wanna call it at the bottom of the door keeps coming apart at the back.
i dont know if you will know what im talking about but there is a little white clip that is stuck into the side panel and a screw holds it to the door from the inside out. well that clip now wont stay on to the side panel and it keeps gettin ripped out and staying with screw so the panel basiclly flaps against the actual door.
i have tried everythnig form super glue to epoxy to double sided tape nothing wants to hold up for mroe than a couple days.
i have been looking for somewhere to get a replacement piece but i cant find anything. if anybody know where to order these or even the aactual name of this part that would be much appreciated.