Theme Toolkit conditionals

Just adding the theme toolkit to a new theme im creating, and a question has arisen.

Can i define one output, depending on another? In practical terms, i mean if someone chooses the blue or purple footer, can i automatically change the font color to white.

the function ive made is this:

function mytheme_footer_color() {
          global $mytheme;
          if ( $mytheme->option['footercolor'] ) {
              print '#footer {background: ';
              print $mytheme->option['footercolor'] ;
              print " ;}\n";
          }
}

So i want to say if $mytheme->option['footercolor'] = #244D83 or #A20675, then print color:#FFFFFF;, else print color:#595959;

but i dont know where in the existing function to put this, or how to write it correctly.

Thanks for any help.