It's unfortunate that your current renting situation sucks, but you're not quite ready for home ownership yet. Some of the things to consider about home ownership: you'll need more than just the down payment for closing costs, also figure in real estate taxes (school, county, township, etc), if you're not putting down 20%, figure on paying PMI insurance. There are plenty of calculators out there to figure the PI, it's usually the rest of the stuff that people don't take into account.
Also, you need to figure in maintenance costs. What kind of condition is a house for $200 - $250K? Can you fix things? If not, you'll be paying to have these things fixed. For example, if your gutter fell off, can you fix it, or would you have to call someone? Do you need a garden hose, lawnmower, curtains, etc.? These things all add up.
I'd save up more money for a down payment, make sure that I had some float money, and really, really, know exactly how much I would need to budget to purchase a house. You can do it, I just think you're too close to the edge.
Also, when you buy a house, think about taking on a roommate to reduce the cost.....or find someone who is handy to rent a room.