Reliable Sources for Replacement Parts?

I have a 1999 Audi A6 Quattro and its front bumper has tangled with one two many parking blocks and lost. Underside of front bumper cover, the molded plastic part that is the color of the car, is badly damaged and the bottom grilles, the ones that cover the fog lights, have popped out and are lost.

I've searched many online sites and nearly all have approximately the same stock (what's up with that?) and most do not carry the bumper parts I need.

Any assistance locating reasonably priced replacement parts will not only allow me to restore our car, but will make my now grumpy husband (can't blame him) a bit less irritated about how badly I've wrestled with parking blocks. Used parts are Aok.

Thoughts?