How does the price you are asking compare with other 306's on the website? you could always go to undercut the competition.

I would have thought a week is not really long enough, but if you need to get rid of it sooner, you could try Ebay, a local motor auction or if the worst comes to it, sell it to a local garage, but ensure you get a decent book trade in price.

Why can't you just part ex it in against your new car?