Don't worry, I paniced jsut like oyu did (I had someone there to help me figure it out when I got freaked

). It's easy form here on - my big trouble was getting the bar off (once I broke all 4 heads on mine the thing was rusted so hard I was worried it was threaded on), but I pried it off like you did and was left with the bolts like you are.
Take out any remaining bolts and the mounting plates however you have to. I had to cut the bolts off as much as I could with a dremel to remove them, since it was rusted to the mounting plate, and it wouldn't all clear the brake lines. I jsut cut the bottom of the bolts sticking out under the car, and it had plenty of room to get out.
You don't need the mounting plate - if you look at the pictures I put on the last page in this post, there's one with the mounting holes when the plate and bolts are gone - that's what the new bolts fit through. You can see in the pictures too how the bolts were stuck to the mounting plate, and how the new bolts fit on. The mounting plate was rusted to the bolts in my case so it all came off in one piece (which was why I had to cut the bolts).
Once everything is out of there, just put the new bar on. The washers go as you described, and the head of the bolt (the parts that snapped off on the old ones) go towards the ground jsut like before. The nut (the removable part) goes on top.
Tightening it properly is kinda hard... you have to get a wrench or pliers and hold the nut on top, then torque/tighten the bolt from the bottom (reverse of how you removed the original ones). I jsut hand tightened it as best I could and had goodyear torque it properly for me (they did it for free) when I got my oil changed today.
You _can_ drive the car without the bar, so if you absolutely can't get the new one on or the old hardware off, take it down to a tire changing place, it shouldn't be more than a half hours labor to do it. Just drive slow (the car drives like shit with no bar).
If you need any more help or get stuck again just post back. Sorry I wasn't here earlier or I would've answered you quicker

.
Also, see the instructions for the bar available here:
http://www.genuinesaab.com/psi/index.htm