Yes, there are people on Craigs that will do it today for 500, so it's better than replacing it unless milage is so high bottom end is no good. The important thing to diagnose before you decide is why it overheated. That may/may not be expensive.
The head gasket.
Blown head gasket, burnt or bent valve, spark plug loose, busted piston, worn or broken rings,
It sounds like you may have a blown head gasket. It needs to be checked out pretty quick because severe engine damage can occur if left unattended.
It will cost you about $743.00 to replace a vacuum tube on a Ford Focus 2002.
I don't know where the thermostat is physically located on a Focus specifically, but if it is underneath the water neck on top of the intake manifold it may be a poor sealant & gasket used when the water neck was mounted/installed. Perhaps you may want to refer to a Chilton's guide for the Ford Focus to replace the thermostat gasket and sealant?
ondo valve cover, bolts remove valve cover, remove old gasket from valve cover and block. clean both surfaces well. put gasket glue on one side of gasket and install on cylinder head. align valve cover than replace bolts . tighten in a cross pattern until thet are snug. don't overtighten.
Loss of coolant with no apparent leak, white smoke from the exhaust. oil level overfull, a white foamy substance on the underside of the oil fill cap, and air bubbles escaping from the radiator. A compression test will verify if the gasket is blown.
Go here: http://www.focushacks.com/index.php?modid=83 Or get a Haynes manual - it's not too difficult.
every 5 years
If it heated up on you, chances are that you warped the cylinder head and now have a blown gasket. You don't give very much information, here.
3-500 dollars
i got estimate of 600 $