Car overheated 3 weeks ago, radiator replaced as well as a new battery, then no heat, brought car back, thinking it was the thermostat. the car needed a new radiator hose and radiator cap. car overheated last night and it still does noy have heat. now the mechanic told me it may be the head gasket cap! help!! i just paid out almost $650 ad now even more!!

I think I answered this already, but just because you installed a new thermostat does not mean it is good. Sure sounds like a thermostat issue.

Could have pop a freeze plug, cracked the head/s or block.

Damp passenger floor sounds like a heater core. What a pain in the a__. Most probably the dash has to come out to replace. That is the only thing I know of that circulates engine coolant into the passenger compartment.
If you confirm this and want to fix it on the cheap, you can put a crossover hose in the engine compartment and bypass the heater core entirely. This is a $5 fix that works perfectly, mechanically speaking. Unfortunately, you will have no heat. Of course, you may decide that is a better option once you hear a quote on getting the heater core replaced.
Oh yeah, get a new mechanic.

remove cooling flute and thermostat fit1/3 off radiator cleaner with fresh water top up 1/3 more in and 1/3 two days later drive for 1 week and flush your system fit new thermostat new radiator cup and antifreeze .notes radiator blockage after removing the thermostat is,when engine is hot top hose expand and is hotter then the bottom hose notes when the fans engage.

It is possible that the pump failed because of an overheating problem. Make sure the fans run by turning on the air conditioning. They should operate as soon as it is turned on. Bad fans are a common problem. The pump should not have been leaking after replacement though. Make sure you have no leaks first and foremost. Then make sure the fans work. There is also a fan control module located in the area under the battery, but it is difficult to properly diagnose. If the fans do not turn on with the a/c, you can jump the wires at the thermo switch. One should be power, and when you jump to one wire they should go to low speed, the other high.
If you like you can ask more questions directly, I was a VW master tech from 2000 to 2008.

SOUND LIKE COOLANT FANS HAS A FAULTY THERMO SWITCH LOCATED AT THE BOTTOM OF THE RADIATOR ON LEFT HAND SIDE.CHECK THE FUSES 8 IN THE ENGINE COMPARTMENT AND CHECK FUSE 16 IN THE PASSENGER COMPARTMENT FUSE BOX.WHEN ENGINE OVERHEATING IF BOTH COOLING FANS WORKING.OVERHEATING PROBLEM COULD BE BLOWN HEAD GASKET.CHECK ENGINE OIL LOOKS LIKE MILK HEAD GASKET LEAKING.SEE WHEN YOU DRIVING LOW AND HIGH SPEEDS THE COOLING FANS SUPPOSE TO BE RUNNING.IF THEY NOT RUNNING THAT IS YOUR OVER HEATING PROBLEM.

most likely heater core and to check if the water pump working..allow vehicle to warm up enough for thermostat to open and check for circulation in the fluid inside the radiator..if see it..water pump works.

check your fins on the radiator and your water pump also check the thermostat

i would try a new thermostat and a good rad flush, and if your running dexcool switch to a green type (prestone, motomaster)
that worked in a ford taurus for us

I had that problem before, the intake manifold gasket leaks. After replacing it runs like a charm. I have an '01 also and still have it.