For follow-up discussion and general commentary on the topic. Comments are sorted chronologically.
Estela,
This question was answered about two weeks ago on e-bible as “Why do Catholics believe that Mary's parents were Anna and Joachim?” You will find the answer to this question there.
The Bible does not say anything about Jesus’ maternal grandparents, so we don’t know their names or anything about them. If God wanted us to know who they were, then their story would have been recorded in the New Testament.