MS - do you have a seat-belt adjuster? You can get them from Mammas and Papas, Mothercare, NCT and loads of other places, and it pulls the band to underneath your bump and stops the worry in situations like this... not that you're likely to have another prang, but it might be an idea... hope you're feeling okay and your neck hasn't started to stiffen or anything. If it was at work, it may be that you see the car around there again, so keep a look out in case you want the number plate. Do you remember any details? Colour, make and model etc, as the police can run a check for you. I would definately report it, just in case she tries to claim saying it was your fault (I'm a bit paranoid, maybe, but you never know what some people will try).
Mumoverseas - that sucks. I don't tend to post anywhere else, as that happened all the time on fertility friend when I used to go on there, and I actually had to hold my tongue a few times on this thread in case it's the same here (but I've since discovered it's not like that...).