98 Ford Contour transmission problems, I need help.?

I was driving my car just fine last weekend, parked it at home and everything was fine never had any transmission issues in the life of the car and fluid is checked everytime the oil is changed. As I was driving (3 blocks from house) the overdrive light started flashing and the everytime the car went to shift normally it would rev real high then jump into the next gear, it would do that for every gear from then on out. The vehicle was towed this morning to Aamco (sad I know but the only transmission shop I have within 60 miles) and they called me an hour later to say everything on the outside of the transmission checks out fine and they see the fluid levels are fine BUT the fluid is old and "slightly burnt" (doesnt smell, I checked) and my car is throwing codes 732 - Gear 2 incorrect ratio and 734 - Gear 4 incorrect ratio. They want 675 to take the transmission off for internal diagnostics and another 600 if they find a minor problem inside they can fix or 1800+ for a transmission put in. HELP PLEASE.