You can't walk ANYWHERE from Pop Century. I'd use one of the many grocery delivery services available. It would be far cheaper than a taxi bill and would take much less of your time.
It's quite a bit longer walk but she could get to Winn Dixie which is up the street from Goodings.
I also would suggest maybe getting a rental car for the day. I got one from National at Dolphin for $24 cheaper then a taxi and I had the car for 24hrs.