Customized google map based on our data (plotting locations from csv file)

The following project requires knowledge in customizing Google maps. We need a 2 maps of Singapore with dots representing the location of our customers (based on post code). There 1864 entries with two columns: post code and amount. First map should display a dot for each post code location or similar. The size of the dot should represent the number of customers for that post code. The second map should display a dot for each post code location or similar. The size of the dot should represent the total order amount (aggregated) for that post code. The result should be 2 links to customized google maps based on the data (a csv-file) we have given you at the start of the project.