Doesn't sound good. My first thought is that the timing belt might have broken (has the timing belt been changed?)
When the starter works, but "suddenly" can barely turn the engine over, it's never, ever a good thing. The fact it seems to have happened all at once really makes me worry that you DID break a timing belt (I believe that if the belt just slipped, you'd most likely have less compression, but it's possible that it would just mess up the timing enough to cause what appears to be too much compression). Does the engine make any odd noises while it's trying to turn over, or when it stalled (looking for evidence that the pistons got in a fist fight with the valves).
I'm curious if the power steering hose blew when the car stalled, or maybe you just noticed the fluid all over the engine when you popped the hood to figure out why the engine stalled. Taking it a step further, if the power steering hose (which runs right over the rear bank timing belt cover) was leaking, it's possibly going to get power steering fluid all over your timing belt, which can lead to the slipping or breaking.
IF your timing belt slipped, BUT not far enough to get the valves into the pistons, its possible that the fix is to just do a timing belt change (around $1000 at most independent shops), or $250 if you DIY (not really a horrible job, but not for someone without the right tools).