This actually sounds like a job better suited to SSIS, since you want to constantly be writing to the same Excel file.

I'd do some Googling on SSIS exporting to Excel; you may need to have a "staging sheet" in the workbook to get the data into the sheet, and then a script that will copy it from there into the first empty column in another sheet.

I know just enough to be dangerous on this sort of thing, so hopefully someone with a little more knowledge will be able to chime in.

Cheers,

EJM