This write-up over at WikiAnswers is pretty good.
According to 13: How to Read, Misa loses her memories related to using the Death Note and retains her love for Light. Since it is in the nature of a Death Note user to "suffer misfortune", Misa falls into despair after someone "like Matsuda" "probably let it slip" that Light died. When she regains her memories by Rem telling her Rem states that if Light tries to harm Misa in anyway she will kill him. Misa responds "I don't exactly want to be loved by a Shinigami, and if Light died I couldn't live on without him. There's no way Light would kill Misa-Misa. And why would you go so far for me." Most likely foreshadowing events to come because Light does die. Despite fan rumors, the cloaked woman who appears at the end of the manga is not Misa, but an unnamed follower of Kira. Misa's fate is not shown in the manga at all; she was last seen staying at the Teito Hotel. Ohba stated that this was simply because he did not have a situation to fit her in.
It may be that the scene from the anime is in the future, because light dies on April 28, 2010, and Misa died on February 14, 2011 (Valentines Day) according to Chapter 110 "How To Read" profiles of the characters.
There's no clear evidence for the suicide on the roof, but there's really little reason someone would be standing on the edge of a roof, on the other side of the safety railing.