I don't know of any current programs to buy houses... those are tightening up with the recent mortgage crisis. But a rental. Take what you are paying her for rent and turn it into rent for a smaller place of your own. It sounds like she (or her husband) resent your presence in her household, and feel like you do not contribute enough, so it's a matter of contributing more or getting otu on your own.
You're being abused, but she's right, parents do lots of stuff for the kids UNTIL THE KIDS ARE ADULTS, and anything above and beyond that is generally because the parents are able to afford it or saved up for it. When the kid is asked by the parent to give teh parent the same generosity as the parent gave to the kid while growing up, it's a different thing... usually the kid is younger and not yet had enough time to save up a nestegg from which to BE generous, and there is a feeling of being emotionally blackmailed by the parent who raised them (at least you didn't tell her that you went through a long and hard labor for her and so she owes you for that)... the kid is often at a point in life where they have other more pressing financial things going on, like kids of their own who have needs, and ... well, although there are a few cultures where the family system is organized to account for the kids to pay back the parents once the parents are dependent, that is not what we expect to do, certainly not while our parents are still young enough to be able-bodied and self-supporting on thier own.
I'm not saying that what your daughter is doing is not mean adn wrong and abusive, just that her motives for what she is doing might be understandable and you might be able to salvage this relationship with her if you understand and figure out how to solve your problems without relying upon her. It's quite possible that your presence in the household is threatening her marriage (hello, you have to know this, right?... it's a classic... mother in law comes to visit & never leaves until after the spouse has been driven away).
What she's doing to you, in response to whatever is happening there in that home, is wrong, but... well... you raised her, so I have to wonder what happened to cause her to be this way. This is not the kind of abusive thing that crops up overnight, so there has to be some history, somethign going on that you migth not understand or might not have thought was worth mentioning... but which is very important.
People don't grow up in really giving households and then suddenly become selfish for no reason, you know?
But rather than try to psychoanalyze her for yourself and recognizing that the conclusion will probably be the same... that you will have to leave (to save her marriage or her budget or her sanity or YOUR sanity or whatever)... my solution would be for you to simply find a very small apartment that probably you wont' feel able to be totally comfortable in, where your furniture probably won't fit, and then get a littel cheap storage unit (I paid $50 a month for one where I live and it was able to keep about half my furniture when I needed to make that happen... it was a godsend!) And MOVE before her abuse gets worse.