HAVANA (Reuters) - A Cuban appeals court threw out a 20-month jail sentence for a dissident journalist on Friday and ordered her to pay a small fine instead, a ruling she said was a win for opponents of Cuba's communist government.

Prosecutors had accused Dania Garcia, who writes for Cuban opposition websites in the United States, with mistreating her daughter in a political argument.

She said the reason she was prosecuted was her support for the Ladies in White, Cuba's best-known opposition group.

"I'm happy. I feel that one more time we, the opposition in Cuba, won," a smiling Garcia told reporters upon emerging from the courtroom. "We're going to keep fighting for freedom and democracy," she said.

Garcia, 41, was arrested last month and sentenced to 20 months in prison after her adult daughter, angered by her criticism of the government, filed a complaint against her.

She was in jail for two weeks before she was released earlier this week ahead of Friday's hearing. The court fined her 300 Cuban pesos, the equivalent of $13.

Elizardo Sanchez, spokesman for the independent Cuban Commission on Human Rights, said her ties to the Ladies in White caused her to be charged and sentenced to jail.

The women, wives and mothers of men imprisoned since a 2003 crackdown on dissidents, staged a week of protest marches in Havana in March and were harassed by crowds of government supporters.

Two weeks ago, the government agreed to let the women continue their weekly marches after intervention by Cuba's Catholic church.

(Reporting by Esteban Israel and Jeff Franks; editing by Anthony Boadle)