Engine Coolant Leak

am not the most knowledgeable about cars so you will have to bear with me. To cut a long story short the temp of the engine hit red and engine was slightly smoking. All to do with Engine Coolant reservoir being empty, topped it up last week and the light came back on. Dad and I had a look today and founf there was a slight leak (now this is where am not very knowledgable)...it is above the fan belt and seems that there is a thin metal clip connecting 2 pipes, now this seems quite loose and looks as if this is causing the problem, no other leaks apart from this....what would be the best course of action? tightening the clip somehow or purchasing a new clip and trying to fit it ourselves...unless there is some other cause of this leak?

Thanks

alex