FRom your description, I understood that I need to convert your northing/ easting data to decimal degrees in excel , s that these points can be located at google maps as exact GPS points, if i am right. If this is the case then you are in a very good position because i am here to help you. Actually i have done my Masters thesis using GIS, GOOgle Earth and Excel. i collected water samples from 40 different places and took the location of each sample as N 11° 37′ 449′ E 008° 27' 868 and then converted this data to 23.11 degree and 71.2 degree format using excel , then i placed all the converted data onto google maps . Each point was shown at its exact geospatial position. You can further check one of my final maps , after interpolations, at my portfolio. Accept my bid if you require your work to be professionally and timely done. I placed my delivery time as 2 days but if you award me the project i will give it to you only in one day