Twentyeleven New Template Selection Problem & other glitches

The site I am working on https://www.iatattoos.com
I customized the width of the front page to fit the sidebar facebook plugin, in doing this I didnt realize that the artists pages were referencing the same file and this made all the artists pages just as thin but without a sidebar. So I made a new template file that refers to some new CSS lines that provide a wider area. I went through all the steps correctly however now I am having trouble selecting this new template when in the “edit page” page. I still only get the same 3 options in the template drop down that Twentyeleven came stocked with. Is there a way to tell it that my “artists.php” file is to be used as a page template?

Also I was not aware that updating wordpress would override my twentyeleven theme and I never made a child theme. So I am assuming I just need to copy the Twentyeleven folder and rename it to avoid losing everything… Is this correct? I assume also that I may need to go through the files and find/replace a few things to make that work?