A handgun would be better but to answer your question, there are a lot of stun guns on the market. I carry and love the X26. Its mega expensive, but it works. I have rode the lighting 3 times and there is no getting out of the pain.
With standard tasers, the attacker can twist or turn and be free from the taser in a second. With the X26, provided she gets a good shot, the attacker has to ride the lighting for a full 5 seconds before it shuts off. She can also hold down the tigger and effectively have the attacker ride the lighting till the battery runs down.
IT points, acts and shoots just like a handgun.