Car Issues

The other day I took the car in for an oil change and found out that I have a leak in the Coolant Reservoir. It is just a tiny little whole. Now I have a feeling that this will need to be replaced a lot sooner than I originally thought. I was driving home from the Dowalters this evening and the van is wanting to over heat. I wish I had taken Auto Shop in High School. I looked on line and if that is what the problem is I can get the part for around $8 at Auto Zone. What I know is going to kill me is having it installed! I am praying that that is what the problem is and that I can find a decent HONEST mechanic who can help me out with out costing me an arm and a leg.
Any suggestions?