I was/am going through financial hardships and I promised Hashem that I will give maaser on any and all income that I receive, because it is a required mitzva. I have been keeping my word. My daughter receives disability of $733 and as soon as it is put in my bank account, I go straight to the computer to donate $74 to a Jewish cause, mostly to help poor people in Israel. Here is my problem; doing so leaves me in a position where I cannot afford my rent (700) or my bills. Thankfully, buying food is not a problem because I receive assistance for that. I don't want to break a promise to Hashem; Do you have any advice on what I can do?
Welcome to J.SE; we prefer broader questions, but let's speak in more general terms.
and I promised Hashem that I will give maaser on any and all income that I receive, because it is a required mitzva.
That's the key right there. See this source sheet from Rabbi Mordechai Torczyner, citing Pit'chei Teshuva YD331:12 and many other sources that maaser is a very meritorious custom and practice, but not an all-out requirement.
Now on to the promise. If I promised God not to eat chocolate because I think all chocolate is non-kosher, that promise was made under faulty premises and is easier to undo. (If I said "I know chocolate is often kosher, but I'm promising not to eat it because I'm on a diet", that's a lot trickier.)
But promise aside, tithing is a wonderful practice, but first and foremost is the obligation not to impoverish ourselves in the process. (Emergency responders have far too many stories of the random bystander who tried to rescue someone from drowning/electrocution/etc. and wound up another victim instead.) You're still obligated to give a few dollars a year to tzedaka, but not all that much. Please find a rabbi you trust, and you can discuss what's reasonable to give. (There are various ways of computing maaser; some deduct a lot of things, some argue it's only on your net profits.)