Thanks so much you guys for all the suggestions

I know there is only so much I can do...I just wish the OWNERS would step up and take care of their animal like they are SUPPOSED to

I just HATE that people get animals and love them when they are little and cute, and then just toss them aside when they get old or sick. I'll never understand it I tell you, NEVER. I am going to see about either bringing this baby home with me, or either bringing it over here to my moms house and keep it here, safe, until Monday when I can call the vet.
God, I have NEVER had to put an animal to sleep, not even one of my own....now I may have to do it to an animal that I don't even really know

This is just SO incredibly heartbreaking for me.
Then I think...geez, it's obviously someones cat that lives around here....is it OK for me to just take it and possibly (I'm sure) have it put to sleep? I mean I know the people who "own" the cat are OBVIOUSLY not taking care of it like they should be....I just don't know what to do. I am so confused.
I am going to go over there again in a little while and check on it...and will probably bring it back home with me, or to my moms...I hope the poor thing lets me pick it up