i built an ebike for my wife using a rear wheel motor kit, and a 48V 18AH battery, thats 860 watt*hours. its good for about 15-20 milesof brisk riding with mostly under 300W assist as long as you keep pedaling too, and will still climb the 300 foot 6-8% grade I live on in a relatively high gear at 10-15 MPH. the motor is rated at 1000W but I have it restricted to 750 and most of hte time its only peak 300-350 output because if you run more power for very long, it overheats.

the bike you're referencing has a 250W motor, and a 36V 8AH battery, thats 288 watt*hours... it would /probably/ do what you want. if she could bring the battery (and charger) into her workplace and charge it while shes working, that would raise it to for sure.