My condo is self managed by an older woman living in the 6 unit building. Can she demand extra money?

I pay my assesment fee every month of $130. Just last month she said she needs all other 5 units to pay her $600 immediatley for the plumbing that needs to be fixed, and the roof. I just want to know if this is legal? I've never had this, or heard this happen to anyone before, and can't find anything online. Any help or advise would be helpful, thanks! I live in Chicago, IL