When Steph first met Dana in The Robin 80 Page Giant: Nature's Bride she had no idea that Dana was Tim's stepmother. All she knew was Tim had had Dana in his car for some reason and that she attacked him due to the cursed amulet she was wearing that made her possessed by the spirit of a woman name Ravenna, a criminal who could control the minds of animals and make them do her bidding.
The possessed Dana wreaked havoc with her animal controlling powers, until Steph finally stopped her by knocking the woman out with her "roundhouse right cross". This was just before Dana's wedding to Jack, which meant poor Dana had a black eye for her wedding.
Stephanie appears to have met Dana as Tim's stepmother sometime in between Robin #99 and Robin #101, as she was talking to Dana about Tim in the kitchen in #101. The two appeared to have a fairly friendly relationship, as Dana was concerned about Steph's cold and Steph pitied Dana for her situation with Jack's depression.
In Robin #124, however, Dana wondered if Tim was still a virgin, citing the fact that his girlfriend, Stephanie, has already been pregnant once.
Dana was aware of Stephanie's death when she was put in a mental hospital in Bludhaven after Jack's demise. When talking to Tim, she said "Will Stephanie come with you next time?...Oh, I'm sorry, Tim, I forgot...I'm not crazy, I'm not!"
Dana's whereabouts right now are unknown, it's confirmed by writer Fabian Nicieza and DC that she survived the explosion of Bludhaven.