In Harry Potter and the Deathly Hallows Molly Weasley finally does have to choke a bitch. Indeed, she uses the reference "bitch ("NOT MY DAUGHTER, YOU BITCH!") before choking the bitchy death eater Bellatrix Lestrange, Lord smoldemort's "best lieutenant". Molly Weasley, the sweet, otherwise gentle, well-curved mother of 7, chokes (figuratively) Lestrange without even touching her.
Molly manages to best Bellatrix, which the combined efforts of Hermione Granger, Luna Lovegood, and Ginny Weasley were incapable of doing. Bellatrix's death frees up Harry Potter to defeat Voldemort.
Molly, who had a bit of an argument with Sirius Black in Harry Potter and the Order of the Phoenix over Harry's level of involvement in the Order of the Phoenix (but had a very friendly relationship with him) inadvertently gets revenge for Sirius's murder (killed in a similar manner by a curse from the wand of Bellatrix Lestrange).
We finally learn a possible source for Ginny Weasley's aptitude at performing the bat-bogey hex. Give Mr. Weasley his props, but the fury would appear to run on the female side of the family.
It would seem that Molly Weasley isn't jailed later on for her killing curse, perhaps because she committed a "homicide in the public interest".