Stray Cat

Maybe contact a rescue in your area?

see if you can find any no kill shelters in your area - or even ask your vet if they will help a stray out if it is injured. My vet will and will either hang onto it until they find a home or give to the no kill shelter here, and they donate their time/work.
We get quite a few Siamese into rescue that have been at a vet's clinic due to illness or injury.
 

I just feel so bad that I can't help him or her, Princess just got hurt so I'm paying that otherwise I would take the cat to the vet, I am waiting on the humane society to get back to me, also going to ask my vet tomorrow when we take Princess in to get her draining tube out, if there is anyone or if she might be able to see the cat.
 
I can get up close to the cat since I feed her but last night she was standoffish also I don't want to be bit by him or her I was trying to see if I can look under the paw sometimes my dogs get those hitchhikers (think thats what they call them). but she wouldn't let me look. 
 
Haven't seen her today yet hopefully she's ok.

First, where are you from?  You might want to add your location in your profile, in case someone here reads the post and is close enough to you to offer help.

Second, it's great you took this cat in.  I understand about the bills.  I found a five week old abandoned kitten in a hollow tree.  I took it to the vet for de-worming, but couldn't afford any more.  Luckily, my friend had told me she wanted a baby kitten so she came with her husband to adopt it from me the next day.  I was syringe feeding it while trying to get it to use a litter box and try some adult wet cat food.  Since my friend wanted a cat, she got all the shots, etc, and still has it.

Third, if this is a stray/feral cat, your best bet for ensuring it's quality of life is going to be finding a free or low cost program that speuters and treats ferals and re-releases them.  Sadly, many no-kill shelters think they are doing good by trying to keep these cats, but they are born and grow up wild and won't be happy indoors.  The Humane Society may find the cat unadoptable and euthanize it.  Personally, I think that would be better than it getting sicker and dying of an infection, but the most important thing right now is to find a way to at least get it treated and then deal with whether or not it is adoptable.