What do you do if there is fluid leaking from the transmission and the car is on and in drive but it wont go forward?

if you have a leak in your transmition the best thing to do is NOT TO DRIVE THE CAR transmition damage may occur meaning $$$$$$$$. if you MUST move the car try adding more fluid. and since its leaking you may need to stop and add more very frequently. on the other hand try to see from where the leak is coming from it could be thru one of the transmition fluid cooling lines that may be loose or corroded that can easily be fix.