Only in America do the honest, decent people put bars on their windows, double lock their doors and hide at night from the criminals who "own" the streets.
Sadly, you will probably not be able to carry a gun. I wish it were otherwise, but our govenment in their infinite wisdom feels that we (sheep) are meant to be slaughtered!
Now, you have a small knife (2-3 inch blade/folding). Here is a nice, dirty little trick that can equalize a small woman against a much larger adversary.
I carry my change/money in my weak hand pocket...I carry a small (cold steel) knife clipped to my strong hand side.
At the first sign of problems, scream as loudly as you can, at the same time toss the change, money into their face, as you are doing this drop to one knee and shove the knife into either the femor artery, or shove it through the testicals into the pelvic girdle...no bone so the blade slips in easy!
Slashes should be kept at the inside of the arms, or above the eyes, so the blood drips into their eyes...a stab to the face should be either the throat, the soft palet (underside of jaw) or through the eye socket..if the knife is dropped, a thumb can be shoved through the eye socket...The scream, toss, drop, and stab can be done in 1 second...attack without mercy. When the man is down kick to the knees, the testicals, throat, rib cage, but keep up the attack until you "KNOW" he is unable to persue you!