Try not to trade-in your Focus unless they are giving a good deal. Do some research and see what others are selling for on cars.com. In my case, I sold my '99 Ford Explorer for $5600, dealer wanted to give me a laughable 2800 (July 2005). It had 105,000 miles, but looked real good.
If you squeeze an extra grand or two out of your current car, maybe you can at least get a used 2005 GT.