I am sure as time goes on she will get over her feelings of anger towards you, you have apologized you can not do much more,perhaps if you said to her you recognize it was a bad time to call, and you won't be doing it again, that might help, only you know your friend, i must admit i am a stickler for NOT calling people at work, i never would unless it is an emergency,as i would not like it myself, i am old fashioned in that respect i guess, work is work to me, anyhow that is just my take on things.

Don't worry too much Donna, if she is truly the friend you say she is , she will forgive you,and she probably did over-react and will realize this later on, and mellow a bit ok.