I had the same mould as you, dont half make ya car stink!!!
Anyway, i used a upholstery cleaner from halford, cant remeber what it was tho but i didnt use the brush attachment i used a stiff placcy brush that i think you can get from halfords and scrubbed like a muthaf**k*r!! that shifted most of the mould, and according to me mum, using a mild disifectent solution (one that isnt a bleach on, altho white interior would look pimp) to kill off the last of the mould!
Then hover the carpet with some of that shake n vac stuff to freshen it up!