Check Engine Light

Hi All,
I just bought a 2005 aveo. Bought it for $50 bucks from an old lady who had it since 2005. It has 76K on it and she says she hasnt done any work on it. I know I need to replace the tires because they are almost balder than a baby's bottom. The check engine light is on and from doing a scan it loks like its a camshaft sensor. This is like a few parted questions..1. has anyone had to replace this? 2. how easy is it to replace? 3. What other items do you guys recommend replacing? I know this car received regular oil changes from her son, but just wondering what else I should change on it. Any helps and answers would be greatly appreciated. I am wanting to get this on the road within the next 2 weeks.

Thanks