Does the $row ('12345' ??) you're printing contain the data you're trying to capture? If not, we'll need a lot more info about what your $row contains.

If so, check out threads here on spreadsheets. There are many re Excel. And if what you find isn't adequate, then perhaps you need to take a step back and learn about opening files; writing to them; closing them, etc.

You'll do yourself a lot of good by using your own efforts trying to find a way to do this. I suggest starting with Super Search and a search term like 'spreadsheet' or 'Excel.'