My neighbour has been gone for a month now, and comes around rarely... she has left her dog outside with no food or water and seemingly nobody has checked on it or come bring it for walks,let it inside, etc. I tried to call the humane society but they haven't showed up or done anything about it, I have been taking it for walks and feeding it and basically am the reason it is still surviving... I have talked to a few people and am trying to find a home to give it to... the owner even asked me when I returned her the dog after it ran into my yard... if I had wanted it. She doesn't want it, obviously... but my question is could I wind up in some sort of trouble even legally for what I'm doing... since I have not actually spoken to her about it..
Should I stop? And just call the humane society again until they do something?

You could, possibly, if the owner wanted to make a big issue out of this, get into trouble. But I also wonder how far the owner could really go - once all you say is brought to light?

Have you called your local police and asked to speak to animal control? Explain the situation and let them come and assess and take charge.

Are you documenting days and times and what you are doing to take for the animal? Any pictures or videos?

If that animal is need of help, I do not personally think you are wrong in helping. What you are doing is being an angel for that dog. Good luck.

I've found in times when there was a situation that just calling the human society or ASPCA got me nowhere. It wasn't until I physically went into one of their locations and had a sit down with someone in charge there did they ever take any actions as far as investigating the situation.

You may want to try that first before you take the dog and give him/her to someone else.

Is there anyway of contacting the owner and just saying "Is it okay if I find your dog a home?" If you can contact the owner don't say things that could upset the owner, no matter how much you want to say about the situation. A pleasant conversation has the potential to go a lot further than one accusing them of abandoning a helpless animal.

If you exhaust all other options then, and only then, I would say go ahead with finding him/her with a new home. But please alert the new owners of the situation at hand so they have the choice to decide if this is something they wish to get involved with should ASPCA do nothing and you're unable to contact the owner.

There is the potential to get in trouble for doing that but if you exhaust all other options and can prove in some way that this dog was abandoned then it may or may not help your case.