I think its a DIY job. But the part is probably expensive. It think it is a very hard fiberglass. (kinda like the piece on top of the radiator)
try using a upholstery clip remover to pry it out. if that doesn't work a body shop will have the 10$ tool
My car looks like it is 4 inches off the ground, so ive always wanted to lower it. But every time I smash this valance on a parking block I remind myself that Its good to not be too low.