2001 Honda Civic Radiator

Hello,
I just had a new cooling fan put in my car 3 months ago because my car overheated and melted the fan. Then, I had my bearings in my transmission replaced a couple of days ago. Now, my radiator is leaking, and my engine ran hot again. I paid $250 for the fan $1250 for the transmission and new clutch and now they are charging me $300 for a new radiator. You would think after spending $1800 in 3 months on my car that I would have a car that runs like a pearl. I am so frustrated with my situation, and now I don't trust any mechanics. Is there some other reason that my car would be running hot. This last time it overheated, they told me it melted the plastic radiator reservoir. I told him give me a new radiator and thermostat and that is all I am doing now. What other reasons could be making my car run hot? The first time I was told the fan melted and that was the cause. This time I was told they are going to put the new radiator in 1st before they could see if there is another problem. I did see the leak with my own eyes under my car, so, I am pretty sure that I need a new radiator. If it was the water pump or a blown head gasket, wouldn't he have been able to tell by just looking? Thanks for your help.