My employee rights from a disability

I have been working for a local law enforcement agency in Colorado as a civilian for about 2-1/2 years. I am suffering from an unknown neurological disease that the doctors haven't been able to diagnose as of yet. i've had this for about 4 yrs now. I get relapses now and then. In May 2008, I was sick and came to work. Usually when I get bad enough that I can't work I go home. I only had 2 weeks of vacation left to use if I get sick. In May I got very sick and continued to work. I continued to get sick and was sick for about 6 or 7 weeks. I usually do not have any problems, but during the time I was sick, I had made a few errors. Nothing life threatening, but they were some mistakes that I don't usually make. I had talked to a supervisor in confidence about this. The supervisor was going to consult with Human Resources to see if things got real bad with me if I would be able to medically retire or have any other options with the city. When she did talk to the person it was found out accidentally regarding the situation of some of the symptoms that I had showed in work by the manager of the dept of the position that I was working at. I didn't take the 6 weeks off from work while I was sick, because I only had 2 weeks of vacation left and no sick time. I couldn't lose my job nor the pay. The manager of the dept heard about my situation in July 2008 and felt that I needed to have a fitness for duty exam done to see if I would be able to come back to work in my current position. They sent out letters to my 3 doctors that were treating and diagnosing me. 2 of them said I was fit to go back to my position. 1 of them said that I wasn't. Because of this I had to see a city doctor and he will make the determination on whether I am fit to go back to work at that position. If it turns out that the doctor finds me unfit to go back to work, does the city have to help me find another job in the city through ADA (American Disabilities Act) or am I on my own. If I do have to go through ADA, what happens to me in the mean time? Can they just let me go without pay? If they can am I allowed to collect unemployment for this while looking for another job? Are there any other rights that I am entitled to in this situation?