A foreclosure actually wipes out any agreements. it could be argued that you and the previous owner had an agreement but since it is not in writing, you are probably in a very bad postion and will be portrayed as a squatter.
I can't give you advise except to say that you should start looking for a new place to live.
Best of luck!
Unfortunately without a written contract it's difficult to know exactly what your rights are. Since we are not lawyers on this site, we can only guess that you will have to start looking for another place to lease right away.
Please do look at Lanlord and Tenant Laws that is available online for the state of California at http://www.dca.ca.gov
Double check with LAHD at http://lahd.lacity.org/lahdinternet/