Dang Squishy! Sorry to hear that! Hope you're okay! 
I probably would've called 9-1-1 or *OPP for that arch-dingbat... but now probably would call the nearest OPP detachment and see what they say. Where did the collision occur?
WTF - how did that moron NOT know he'd hit something?!? 
I think the more detail you have, the better, including but not limited to all of the stuff you have plus:
- Traffic conditions
- Could he have safely merged at another point (well no kidding)
- Did you make it apparent you wanted him to stop
- Where did you lose sight of him/stop following
- Did he gesture/indicate anything to you
- How was he driving prior to/after the collision
- Were there other occupants of the vehicle, if so, did you observe any reactions
- Damage to your vehicle (do you have photos?)
Things like that. Not saying all of that would be required in the report, and I'm not an expert on this by any stretch, but since the driver caused a collision and took off, chances are they'll find him and you'll probably end up testifying in court.