Chances are your gonna take a huge loss money wise. Unfortunatley the resale value of the focus isnt that great. even with the low miles, you wont be getting much. Look on kbb.com or nada.com for current values.
And you said you like the car and are not having any problems then why get rid of it?
This guy has 105k on his, and sounds like little to no problems
http://www.focusfanatics.com/forum/showthread.php?t=306727