My Aunt died in late1996...My sister& I are in the will

My Aunt died in late1996...My sister& I are in the will yet intentionally left out by the public admn. to benefit others. YEARS later we find out. Probate was held in San Francisco. We live in WA. State. I knew NOTHING about "Probate"- There's a clause in her will that states this, "My estate includes the value of property to which section 2044 of the Internal Revenue code 2044 relating to property to which I had a Qualifying income interest for life applies, the executor shall not recover the amount that my estate isentitled to recover under section 2207A of the IRC from the person or persons recieving that property.My Aunts estate is still not closed believe itor not & I am hopig someone inhere knows about these types of IRC Codes..? What can I do..? Thanks :)