1995 Dodge Caravan Lost Gear?

I was driving my 1995 Dodge Grand Caravan on the highway at 70 mph with the cruise control on when suddenly the car lurched, the rpms went to 5000+ and the speed slowed to 60 mph. I disenaged the cruise control and slowed down. The car ran fine at slower speeds but I couldn't get it to go past 60 mph. The transmission fluid level was fine. Since I was 150 miles away from home at the end of a 6,000 mile vacation, I limped home at 45-50 mph. I've come to the conclusion that I lost the top gear.

With 197,000 miles on the vehicle, I don't want to sink a lot of money into it. What do you think the problem is and what do you recommend I do?