How can I change my my visa status to stay in Bolivia?

Hello, I am a US citizen I am already here on the 90-day tourist visa because i did not have time to get the "visa de objeto determinado".

I am here in Cochabamba because my Bolivian mother is 90 years old and needs someone to over see her care and accompany her. I need to stay here indefinitely and I really do not want to go back to USA and leave her alone. I need advise...... is it possible to to apply for residency without have to leave the country? I could go to Peru for a few days.