Here's the attached file (scoreboard.zip) already modified to use longer names.
On the example pic, you see (marked in yellow) the "home" and "visitor" you should replace with your own teams, for each game. I also added a html comment (the statement in blue) to help you to find the correct lines.
SO download the zip filed, and take the html file in it.
THen, open it with that software (if you're using windows) :
http://notepad-plus-plus.org/
And just change the names as I explained. Then, save the file. Now, double clicking on it should open the scoreboard with teams new names.
If it's not working, right click on the saved file and open it with your usual web browser (you should have an option visible in the menu, like "open it with firefox" or "open it with internet explorer").