Help! Water on the knee or just swollen?

We were involved in a car accident about a week and a half ago, and my wife hit her knees on the dashboard pretty hard. at first there was bruising which is still there, and now there seems to be water or swelling on one of her knees, and she is feeling a bit feverish. just wondering if we should put hot or cold compresses on it or any home remedies... i know the obvious answer is go to the doctor but she is currently uninsured as we are in transition to my company's insurance we will go to the doc if we need to just trying to avoid costly medical bills. thanks.