Just open this file with a notepad, add your new colors, and save the file, like this for instance:
...
magenta = $3034C8
orange = $0080FF
pink = $FF80FF
MyNewColor = $112233
purple = $C000C0
red = $0000FF
...
The color $112233 means blue = 11, green = 22 and red = 33.
$11 = hexadecimal value of blue (17 in decimal value)
$22 = hexadecimal value of green (34 in decimal value)
$33 = hexadecimal value of red (51 in decimal value)
The hexa value for red/green/blue can be from 0 to $ff (0 to 255 in decimal).