Overheating and Mechanic-Less

[rock88hard]

My 1999 just started overheating on me after checking my fluids. At first I thought I just didn't put the coolant cap on tight enough, since some fluid actually sprayed out into the trunk. I filled back up with coolant from the nearest gas station, and the gauge was still fluctuating. It would go into the red zone, then back to normal. It either over heating for sure, or burning off the fluid that sprayed everywhere. If I drive more than 2 miles, I'll get a trunk full of smoke.

Some background, I did get rear ended last year, approx 2k miles ago. This was the first time I took off the cap since the accident. The lady locked up her brakes and I threw my Boxster into neutral right before impact. The dip**************** mechanics at Richlin Imports, harrison city, pa said nothing was wrong. They also did something that causes my horn to go off when I pull on my steering wheel to get out of the vehicle. They refused to look into the horn thing, so I just pulled the fuse for it. Still not sure what mechanic to go to next.

I know this is nothing to just mess around with so, Anyone out there know where to start?