EB Calendar Tweak Override

Tech Support:
I have received help from you twice before on the EB Calendar font color tweak. The fix is located in the forum post http://stackideas.com/forums/calendar-plugin-i-need-to-tweak-the-font-colors-again
My question is how to create an “override” so that I don’t have to repeatedly do this. I am a real novice when it comes to “Overrides”, but I want to learn. Can you give me a step by step on how to take the code....

#easyblogcalendar-module-wrapper td,
#easyblogcalendar-module-wrapper td a{
color: #000 !important;
}

and add it to my template.css file via an override?

I am asking because I think I sabotage myself when I change my template in Artisteer and give it a slightly different name and upload it to the site and set it as the new default template. I think you are going to tell me that there is no way to create an override if the template file gets changed to another one. But I thought I would ask before I go and paste in the code again. But like I said, I am a novice at overrides.
Thanks in advance!
Michael Leavitt - Orem, Utah - http://www.TheHomeInspector.com - Michael Leavitt & Co Inspections, Inc.