help for audio codec using VHDL

i am a begineer at using altera DE2 board and VHDL. i have to complete my project with in 10 days time but dont have any idea of where to start and how.. help .........

i need to build a duplex audio system that works similar to a phone but here CDMA must be considered.

first i would like to have some good advice on where to start and how .... on audio CODEC

any help would be more than appreciated