Which part number is right for A4 gearbox

[IHK 11]

Hi im trying to find a gearbox for a 2004 Audi A4 1.8 turbo cabrio. I need a 5 speed manual. I bought a new gearbox off eBay which i was assured would fit but didnt and now the cars in the garage on a ramp with no gearbox. Ive found some numbers on it which are 012409355BF   012409131L  0124091311   012101211AB    HFD11054.  does anyone know which is the part number i need to be looking at. Apparently there are a lot of different gearboxes with different fittings. Any help or advice would be really helpful. Thanks.