Accidently put tranny fluid in radiator

I have an '04 Dodge Durango it has 42000 miles and it is a 5.7 liter engine. My husband was going to put Antifreeze in it he had 2 jugs side by side and they are both blue. He grabbed the wrong one and it was tranny fluid he began pouring it in and realized he had grabbed the wrong one. So we started filling it up with water and trying to get it out when we were done there was still a little floating on the top of the water. I don't think he put very much in there. So we went ahead and added the antifreeze. It has been a week since this happened. The car has been running good so we were not worried. This morning though the car over heated and steam was coming out when we stopped the radiator cap was loose. We went ahead and added more antifreeze and water and tightend the cap and I drove him to work I thought it was going to overheat again the temp. Gage went above normal for a few seconds but came back down. Should I be concerned and what should I do? I was wondering if having a professional radiator flush done on it would make a difference or are we screwed? Help please