Lost my admin status to standard in Yosemite

My daughter was using my computer and got the locked Safari warning that gives a telephone # to fix it, she called it, allowed the "tech" to remote search and download to desktop logmein and a LMIRescue.pkg.zip. Thank God she did not give out cc/banking info but gave my name and phone #. Somewhere in the last day and a half of trying to figure out if all's ok with the system, I lost my admin privilege, it's now standard. There is no other user to work with either. I've tried all kinds of suggestions going into recovery and single user mode to no avail to fix it -using the sbin and system library group admin root commands etc. I can't even get my seagate backup to return to an earlier date (that got messed up too by the way somehow) with the Macintosh HD disk to see if that can resolve it. Can someone help me fix this with updated info on how to reset or create a new admin in Yosemite? My mac is from 2009 by the way.