What does this mean?

Ok well I have a sucky job at a gym right now and I applied to this one job at a health office and when I turned my application in, they asked if I had a minute to interview. Well this was this a week from today. I called them on Monday and asked them if they were still hiring for the receptionist position that I applied for and the lady told me yes, and that the supervisor just hadn't gotten around to looking at the applications yet. Well then yesterday, they called me to come in for a 2nd interview on Monday. So does this mean I have a good chance at getting the job or what? I am really wanting it and I even wrote a follow up thank you letter that I plan to mail after I go to the 2nd interview.... what do you think?