I would say you should just do a full rebuild, about $2000-$3000 at a shop. Call around you might find it cheaper.

 

Wow,I lived in Ft.Worth While I was in the school just north of Dallas,I wouldn't even try driving it in that heat,specially knowing you have a potential head issue,VERY lightly pressure test it but if you're smelling/seeing coolant in the exhaust it's a big repair,bite the bullet and have it towed.Hydrashocker is all over it,rebuild it and get clear of all the probs.Even if you get away with head gaskets AND the heads don't need to be resurfaced you still have weaknesses from the over heats,the engine was stressed and needs more than a band-aid.Ford used to have me sit ontop of engines with a new ballhone and work on individual cylinders for about 20 mins to a half hour or more then install .003 over piston rings and send em out the door.It was that kind of crappy dealer authorized stuff that made me leave Ford. BEst advise...FULL REBUILD

 

I would suggest stop driving it before something worse happens.

p.s.>> I love my 4.7, especially since Im getting between 17-20 mpg. :-D