MS Office add-in for version 2000, 2003 and 2007

We need the development of an add-in or plug-in wich integrates in MS office 2000, 2003 and 2007. The add-in must add a CSV file with same name and location as the file the user want to save and have a check button to activate the function, if the function is activated then it will ask the user some additional data like "Meta info", and then parse to the CSV file. The extension of the CSV file will not be .csv just the format of the contents on the file. The extension will be specified later. Thanks in advance