Amica auto box problem!

As title has anyone got a auto box for a 2001 1.0cc hyundai amica gsi?? Or does anyone know where i can get one or who fixes them cheapily ?? Mine still goes but when its cold it sometimes wont go in to drive ! Ive been told its one of the rubber seals inside the box loseing pressure and the drum not filling up quick enough .. Does anyone know who could solve this for me ? its only done 36k from new and to good to scrap when it eventually gives up the ghost ..Thanks in advance