Toyota Repair: 93 Camry Overheat +Engine Vibration, losing coolant, engine vibration

Question
Hello,
I have a 1993 V6 XLE Toyota Camry with a 200800 mileage.  The car is being serviced regularly with oil change every 3000 miles and the last timing belt change at 180000 miles.  The problem with the car now is that it will overheat after I get off the freeway after a long distance drive (50+ mile).  It overheated only twice while driving on the freeway, but will always overheat after I exit the freeway and drive for another 0.5 mile and with constant stoppings.  The car will start this loud fan sound whenever I accelerate the car after stopping at a light or a stop sign when the car is overheating.  (it is like forcing a fan to rotate sound?  this had never happened before until the car started to overheat)  What i also noticed is that when I start the car for the first time of the day, the engine will vibrate for about 10-20 seconds and then settle down.  (the rear of the car also has this weird noise but not loud)  This also happens when I start the car again after a short drive with a 10 mins parking with the engine turned off.
My major concern is the overheating plus the fan? sound.   My mechanic (not from a Toyota dealership) tried to replace the thermostat but it didn't solve the problem. The car was constantly losing coolant so he replaced a pressure cap and that solved that leaking problem but not the overheating.  He then tried replacing a sensor (not sure which one but is the one on the left near this plastic coolant container but under it).  The radiator is a brand new one changed last summer.  
I"m tired with this guessing and testing which doesn't seem to help at all and having me to spend innocent money.  I have read through some of the Q&A that are posted online.  Can this be a gasket problem or a radiator clogged problem?  And can this overheating problem also be the cause of the engine vibration problem?  How much does it usually cost to have a gasket change?  Are there other posibilities to this problem?

Thanks for the help.  I really appreciate it.

~Jennifer

Answer
I don't think the radiator is the problem because you said is was already replaced along with the thermostat, the fans are electrical cooling fans and I don't think they are the problem unless the fan is hitting some obstruction like a broken fan housing or something that is keeping the fan from turning, let the engine idle and come up to operating temperature and see if the fans come on and if they are causing the noise, these problems may be related and again maybe not, I'm not sure, noises and vibrations are hard to diagnose without being there, the first step is to checkto make sure that the cooling fans are working correctly, start the engine and turn the a/c on this will make both fans start, see if they are turning and not obstructed, you can let me know and I can go from there.