Automatic Gearbox Problems again!!!!!

Hi all,just want to say first off cracking day at Coventry despite weather and it was great to meet the SE/SC/SW guys and get to my first z meet for years.

Now i need some serious advice.On the way home i thought id poodle along and stuck the car into cruise control,all was ok for about 20 miles,it then made a loud crunching sound.I turned cruise control off and the crunching went and was driving normally again,after a few more miles i noticed the car was accelarating but not changing gears at all..it would rev,accelerate but not change gears.

I decided to pull off the motorway to investigate and stopped at end of junction.As i pulled away the gears sounded really grinding,crunching sounds up to about 30 then drove ok again,this happend a couple of times til i could park up and look at car.

I opend bonnet and there was a sort of bubbling sound from under engine,i let it cool down and checked the auto oil level..No bloody oil in box!!!!,it was fine before i left and has been fine for about a year with no oil loss,this was infact longest journey car has been on as i only usually go to work in it about 10 miles each way.

I walked to a garage and bought transmission oil and filled it up hopeing it might build some pressure and move again.

Put car into reverse,nothing..the car just revved and didnt move...into drive,one or two a loud crunching /grinding sound then it would move.

Decided to get recoverd home and trying to push the car into position in neutral and handbrake off the car was really hard to push and the grinding/crunching sounds.

Now this is the 2nd auto box its had in just over a year..is it now the time to get manual conversion.or is there some temorary fix that might get it going again?.

My honest opionion of these auto boxes is now they are the biggest pile of crap ever made,if i go the manual route im going to be z less for a few months though until i can afford to get the work done.