payno-wba

hi there just got an a4 s line quattro and it has the bang and olufson stereo upgrade which i want to be able to connect my ipod to,what is the best way of doing this,do i need to get that interface thing that goes in the glovebox,audi want £500 for the pleasure and was wondering if there is another option,tried connecting through aux socket but audio is poor. cheers lee