Don't wait too long to repair your roof if it is leaking. If you found the leaks because of discolored spots on the ceiling below, it may be doing permanent damage. It is probably leaking in more spots than you see. A lighter color is always better. Although adequate ventilation will carry away hot air, much of the heat that you feel in your house is radiating from the hot roof.
Ventilation only helps a little to reduce the radiant heat.