[s-cars] head gaskets blown...

[Twobro12 at aol.com]

hey, my car suddenly started jolting yesterday and I had an immediate loss of power (strange smell coming from engine bay/exhaust also), i pulled over and called AAA to have it towed.  turns out i blew the Head gaskets.  At the time i was only engaging first gear, and driving at slow speeds in traffic.  I also checked my thermometer and it was reading on the cool side (warmed up but not anywhere near hot, just average).  Anybody know how this could have happened?  what should i pay for the repair?  thanks