it is difficult to fit the seats from later models such as the 33 since the spacing of the seat tracks is different. Unless you have a way of modifying the tracks so they can fit the job will be very difficult. Perhaps seats from another Alfa would fit, like an Alfetta GTV, but you will have to measure them up first.
It might be less hassle and more straight forward to have the seats repaired or re-upholstered, the cost isnt actually all that bad, contrary to what people think.
best of luck,
Josh.