Color tools

I have Excel Version 12.3.6 (Yes, I know it's old).

 

I want to be able to put in my own HEX color or select one from the color wheel.

 

But I don't see any other colors available except the ones in little boxes that I can click on.

 

My only other option for coloring are NO FILL.

 

I do see the dropper icon and PICK A COLOR written next to it. BUT I cannot select it because it's been grayed out. 

 

How can I access more colors by selecting one from the color wheel (which is not showing) and put in my own color HEX code (which I see no spare for).

 

If you're gonna tell me that I can update... does Microsoft offer free upgrades like Apple does? 

 

Thanks.