I would have to agree that breeding is a bad idea. You mentioned in one of your other threads that she is unregistered, so technically she is a grade horse and not a quarter horse (though you could call her a "grade quarter horse" if you are certain that she is one). I also don't think that you can be sure that she has wonderful bloodlines if she isn't registered, and even so there is nothing to prove that she is actually attached to those bloodlines.
Of course, since she is unregistered her foal would also be unable to be registered, making it another grade. Since she is only 13 hands not only would many people be leery of buying her foal, but they would probably also question whether or not she is actually a quarter horse. (Not that there aren't ones that small, but you would want papers to be sure.)
Are you simply feeling stuck with her because you cannot ride her and cannot sell her? If so, post some more details so we can help. Where are you located? Maybe someone here lives nearby and has time to help you out a bit, or knows of a person/barn/rescue that wouldn't mind taking on the mare (probably for free, mind you) as a project or to rehome.
If you don't know what to do with her but want to move on to another horse that is more suitable for you, rehoming her for free to a trustworthy person is probably going to be your best bet. She's cute, but definitely small and with some conformational issues that sound like they'll need addressing (the interfering that is causing rubs on her legs). Where have you put ads up?