So one of my fog light bulbs died on my '94 TSi AWD so I bought a set of Sylvania uber-white-expensive bulbs to replace them. I got down on the ground and saw two no screws holding the fog light cover on the housing, but I saw three screws that look like they're holding the lights themselves on the car. I'm assuming I'm going to have to take the the lights off of the car and access the bulb from the back somehow. (Please correct me if this is wrong) The problem is that of the three screws that each light has, the two larger ones, the ones it seems I have to remove, are completley rusted in place. Being a bit of a DIY newbie I'm not sure exactally how to handle this. My questions are these:

Am I approaching this problem the right way or is there some other way to get the bulbs out of these lights that I'm just not seeing?

Assuming that these rusted screws need to be removed, will some WD-40 do the trick or am I going to need to drill em out?

Thanks a lot, and again, please excuse my newbishness. I'll get this down sooner or later