Get a Dension kit,it works with the steering wheel controls.It plugs into the back of your HU where the multi-changer would connect.Then what happens is your 1-6 buttons on the HU become your playlist's 1-5 are the first five play list on the i-pod pressing button 6 allows you to select the remainder of your i-pod playlist's using the fastforward or rewind controls.
Lots of people say that you are better getting a Connects 2 kit which does the same but is cheaper,i got the Dension kit for £100 and in my opinion looks more a complete job than the connects 2 which as a big metal box which you have to try and hide somewhere and doesn't come with a cradle.
Also if you looking at a Dension kit make sure you get the new version which only came out a couple of months ago.
This is were i got mine from.
http://www.gadget-and-gizmos.co.uk/dension-icelink-plus-renault-update-list-p-177.html
Ref fitting.do it your self it's really easy,what i did was srew the cradle into the fascia that holds the hazzard/doorlock/heater screen switches then got a replacment from Reno for £14 for when i sell the car,it makes it look a better job than using one of those brackets that won't damage your car.