Add TL Symbol to Character Viewer (Unicode 20BA) [TL simgesi]
Here is a reference to a font which will give you the character you are looking for in Character Viewer

http://m10lmac.blogspot.com/2012/05/font-with-new-turkish-lira-symbol.html

You may need to deactivate some other font if that has an interfering character -- I had one called PT on my machine.