Toyota Repair: Least cost: new eng, mechanic, or selfrepair?, blown head gasket, coolant fluid

Question
Hi, hope you can help me.  1991 Toyota, 2WD, 4 cylinder, manual transmission, 109,000.  I overheated my poor truck driving on I-44 to St. Louis.  Now it seems that the coolant fluid I put in the radiator is ending up in the oil crankcase-does this mean I have a blown head gasket(whatever that means)?  I hate to junk the truck coz I bought it thinking Toyota's get a lot of mileage & was hoping to get 200,000 miles before buying something new.  Money is tight, so I need the smartest,least expensive option:  A. Pay through the nose to some mechanic for repairs(I don't personally know/trust any small eng/foreign eng specialists) B. Buy a new engine  C. Junk the truck or D.  Get the Chilton's and try to repair myself.  I'm no mechanic, but I'm sorta resourceful and I have helped the forklift mech. where I used to work drop&change the tranny on an 8,000# forklift plus various other repairs, but no small engine, tight workspace exp. I'm not under any deadline to get it fixed & can carpool for wifey, but I would like to drive the p'up again someday, basically I have more time than money & wish I could just fix the #$@* thing. Could you also ballpark a cost for options A B & D?  One shop quoted me $650 over the phone to replace the head gasket. Any advice would be greatly appreciated.     Respectfully, Danny in Springfield, MO.  

Answer
The $650 estimate to replace the headgasket sounds like a real good deal. The reason the headgasket failed is probably that the engine overheated because of another problem with the cooling system.
Unless you have all the needed tools and experience you should not try to replace the headgasket yourself.