Guaro,
I'm not going to get into a flame war and I don't appreciate your name
calling. You want someone to think about your problem, research it, and give
you code, without having to think through it on your own, that's obvious
from this particular posting. Your other posts all address specific issues
(printing PDF files, determining results of SELECT queries, etc...), this one is
more like "I have a program to write, how do I do that?". It's exacly like the
ones that appear constantly from students saying: "I need to write a
program to open a file, populate listboxes, user presses button and some
calculations are done. What do I do?". So please control yourself if someone
asks you to put a little effort into it.

Looks to me that you need to:
1. open a text file
2. read it's data
3. open an Excel Template
4. populate data into cells
5. save workbook.

Have you looked into Excel Automation on this forum? Have you used MSDN
to look at opening/reading Text files in .NET?

Each of the above points is AMPLY covered in this forum and elsewhere.
Have you spent time researching these points using this forum's searching
capability? Or maybe GOOGLE?

If you have not, then do so, write some code and then if it doesn't work, ask
for help with the part that is not working and everyone,
including myself, will be glad to help. Otherwise, don't expect someone to
take their own time to do work that you should do.

Good luck, and hope to be able to help with your code soon.
-EM