The "noch" in this sentence is a bit tricky to translate into Englisch. It basically means that the requested action has (or in this case, hasn't) taken place before the end of a certain time period. The time period isn't specified, but implied.
Let's say person A asked person B the day before to give Miss XYZ a call. Then, person B had until the end of the day to "perform the task", so to speak. The next day, person A ask whether person B did give Miss XYZ a call before the end of the day. We're not necessarily talking about the end of the day as in midnight, it could be the end of the work day, before Miss XYZ goes home or something like that.
So, you could translate
Hast du sie gestern noch angerufen?
as something like
Have you given her a call before the end of yesterday?
Have you given her a call in the remaining time of yesterday?
Have you given her a call, while it still was yesterday?
But this, of course, isn't very smooth English ;)
You can use "noch" not only with time, but in a similar manner with space:
Ich habe das Hemd noch in meinen Koffer gekriegt.
This sentence implies that the suitcase was already full, but the speaker got the shirt in there somehow.