Take a deep breath. I don't think you're screwed, I think things seem a lot worse to you right now than they really are.
First, your credit score will likely improve just by settling the debt and having them show the debt as "settled in full"--that is not as bad as an outstanding bad debt. Second, as best I understand it, the "dent" in your credit from this will only affect your credit score in any significant way for maybe 2-3 years, and assuming you don't have any other late pays going forward, your score will steadily increase over that time. By way of example, I personally have a medical debt that went to collections (I just lost track of the bill), I paid it off four years ago, it still shows up on my credit report, and my credit score according to Quizzle is 794.
There are also other ways to raise your credit score. Do you have other credit cards, loans, etc. that are showing up as current? How much of your available credit are you using? One way to increase your score is to keep your % of credit utilization low (meaning you have the highest possible credit limits, and you are not using very much of it). This contributes greatly to my current high credit score.
Finally, having a high credit score is not a prerequisite for financial success. It doesn't keep you from saving money, investing, paying off debts, or a host of other things. You can find landlords that will rent to you, and if you can demonstrate that you're responsible financially other than this one thing, I think you could even get a mortgate through a place that will do manual underwriting and not just blindly screen based on credit score. Even if you took a hit on interest rate short term, you could likely refinance once your score comes up.