For menu link color, you can change it with the following custom CSS, put them into “OldCar options > Custom code> CSS code”:
.primary-navigation ul li a,
.primary-navigation ul .sub-menu li a{color:#000;}
For change the hover color, just go to “OldCar options > Custom style > Active and Hover Color Of Menu Item”
I will add a colorpicker and option for changing the menu link color in the theme options in next version.