I wouldn't replace the whole quarter panel, if you can get it of, just use a rubber mallet and gently tap it out.
That other one you may want to have professionally done if it's that big.
BTW, never use those little dent pullers that auto parts stores sell, they leave little dents where the suction cups go and you can even see the dents on their commercials if you look really close.
Is there any paint damage?