application linked with excel

i need application that works under windows OS (XP,VISTA,7) this application should be light as its only to transfer data to an available excel file. This data is going to be in text file, these details in the text file will be about 30lines, i need to specify to this application which line to copy and transfer to the excel file and in which cell to post in excel. The data will be numbers and names. I need the code with some info so i can easily edit them in the future if the excel file format will be changed.