How long do i have to bring my account in good standing by paying the past due amount?

Im currently am going through Probate for my moms home, I received Letters Of Administration. I have been about 8 months behind on mortgage payments, the mortgage co has been very patient with me in as i let them know my situation. The mortgage co wanted a new deed with my name on it to do a name change, i told them it would take anther 4 months to close the probate then i would receive a deed with my name on it they then tol me to send what i had which was the letters of Administration so i did and i still had not made any mortgage payments. I received a Notice of Default and Election To Sell Under Deed Of Trust June 24, 2011, i want to bring my account in good, what do i do? I tried to contact the mortgage company and they wont talk to me until i send in the Letters Of Administration which i faxed to them June 26, 2011. They told me to call back in 5 days to see if they received it.