Buy it for what's she's asking if it makes sense. The title company will take care of paying off all the liens before she gets a dime. If you want it, get it under contract ASAP, and work it out later.
The question is does she want to sell? She can probably live there right now and the cost is less than rent. I believe if the bank forecloses then the HOA lien gets wiped out. Your best bet is to wait until bank forecloses and buy it from them.