I just did similar work on my C230 and it looks like it is pretty similar. They have some on Ebay for 54.00 for yours, you have to transfer your motor over which is the easy part. Leave the window up, drill out the 4 rivets with a 1/4" bit until the head comes off, then punch the rest through with a punch or nail or something (and hammer). A mirror helps a lot as was said, I bought an inspection mirror a long time ago (telescoping handle with swivel mirror on it) and I have used it many times. The regulator has a little square plastic "cam" that slides into an aluminum channel that is attached to the glass. There is a black clip that you pull off so you can slide it out. I bought the rivets but they were a pain (literally) to install as was said below. Bolts will work but make sure to use nylocks or locktite or something so they can NEVER get loose. One of them might be a little tricky to get on. Keep in mind this is my experience from the C series so I can't swear it is the same but same year and the regulator looks the same.

Mike

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1998 C230 330,000 miles (currently dead of second failed EIS, yours will fail too, turning you into the dealer's personal human cash machine)
1988 F150 144,000 miles (leaks all the colors of the rainbow)
Previous stars: 1981 Brava 210,000 miles, 1978 128 150,000 miles, 1977 B200 Van 175,000 miles, 1972 Vega (great, if rusty, car), 1972 Celica, 1986.5 Supra