i seem to have acquired a feline stalker

Okay, so somehow i can be the mean and scary redheaded librarian on the rampage striking fear in the hearts of patrons everywhere, but kitties (and sometimes a stray dog or two) in need of a warm hearth and/or heart seem to instantly sniff me out. For the last three or four days a little grey tabby has been hanging out in front of my house, begging me to let it in, talking to me through whatever window it hears my voice, despite repeated warnings--hisses, growls, moans, screeches, etc. from my resident cats--and no encouragement whatsoever from me. I'll think the animal is gone only to stumble over it on the front porch, have it appear around the corner of the house, or hear it mewing outside the kitchen window.

I don't have the heart to call animal control because i don't want it put to sleep.

It doesn't have a collar, but it is a very friendly cat and doesn't act like a street cat or a feral cat. It doesn't look starving, and it looks well-groomed. It doesn't seem to go anywhere else but here so i'm not sure where it's being fed.

I cannot take in another cat--three is definitely my maximum, so i'm still checking around the neighborhood and looking into rescue groups and no-kill shelters--i'm even willing to donate for upkeep--(the damn cat must have known that when it came into my yard.) I know its totally silly all these homeless pets in the world (and i already donate to ASPCA & the Humane Society, etc) and i'm worried about this one sleeping on my porch--oh well that's just me--once an animal finds me--its my problem--just call me a sucker :)