My 1996 ford thunderbird is overheating and when it does so , it leaks water and anitfreeze from under the car and from top

Sounds like a bad waterpump. Waterpumps have a "weep" hole built into them - it's an early warning system so you can spot a leak before bearing locks up and does major $$$ damage. With age and suspected mileage (and if you plan on keeping car for awhile, I'd replace the following:
Waterpump, thermostat, radiator cap and flush & fill system with new coolant.
My reasoning is: if you replace only one part the others are bound to go bad shortly after and you'll be investing time,labor and $ in anti-freeze (coolant) multiple times. Do it once and be done with it.

It could be a number of problems. If coolant is not leaking from the radiator or bad hose the water pump is the most likely culprit. There is a weephole that the water can leak out of and the only way to repair it is to replace the water pump. Good luck