Dashboard / Auto Gearbox problems

I would be very grateful for any ideas on a problem with my Audi A4 1.9TDI 90BHP Auto 1996N Saloon 195,000 miles.

Before the main problem arose the car sometimes only operated in 1st and 2nd gears but would recover to operate properly before the same problem started again.

The following problem happened suddenly.

The car now only operates in 3rd gear, the reverse gear is O.K.
The airbag warning light goes off only after the engine has been running for two minutes.
The rev counter isn't operating and the warning lights flash and the dash gives the three warning bleeps.
The air conditioning will not start but blowers and heater are O.K.

Apart from the above the car is perfectly alright in all other respects and all fuses have been checked on the drivers side. The water temp guage is at normal and the oil levels etc., are all correct.