gearbox trouble

[dirty harry]

hi
my 33 has recently not been going into reverse, well being temper-mental. today i drove it to school as good as ever changing gears parked it outside school on the street and left it there. came out of school and tried to start it in neutral and it jumped backwards. i thought this was just an odd occurrence so i put my foot on the clutch first gear started and tried to pull off from the kerb and nothing, engine started fine but when i lift the clutch pedal so i get forward drive just nothing its like im trying to rev the car and go with the clutch pedal in which i assure i was not however i put it in to revers (it went in to reverse fine the whole time i was trying to fix it might i add) and it went backwards fine. so i trying just putting it in first and just let the clutch out with no revs to see if it would stall, it did (eventually) but i had to completely release the clutch pedal when usually about half way it would violently stall. i might also say that it was a peaceful stall (if there is such a thing) it was almost as though i had just turned the ignition off. so i called the RAA out and he took at max 5 minutes looked over did exactely what i did and then said there was not much he could do on the side of the road and it was "typical alfa" thanks jerk were my thoughts so i was just wondering if anyone could suggest a reason or a problem as me and my dad are gonna go try and fix it or tow it on saturday, so are there any things i should look for etc. and just so u don't say it i would drive home in reverse but i am in the adelaide hills and go to school in the city so its about 30km in revers up twistie roads lots of traffic lights or a freeway argg.
thanks for anything
harry