Most of the Sync audio and hands free features are available in aftermarket units. I have an '08 Fusion (okay, it's the wife's) with SYNC and all of it's functions can be duplicated except for the vehicle health reports. Your '04 won't support that feature anyway.
Visit Crutchfield.com and check out a Pioneer, Sony, Kenwood or Alpine double din navigation unit with USB, ipod and satellite radio options and bluetooth. You'll spend less and better support. Ford won't help you retrofit SYNC. You'll have better support from the aftermarket.