Probate: The Promissory Note / One-Third Of Property Value

What is the name of your state? California
I purchased property with my mother and sister, each as to an undivided interest as tenants in common, in the state of California. I paid all the cost for my mother with the understanding (promissory note) that she would repay me at a latter day or at the sale of the property. I brought out my sister’s share in the property. My mother died ten years ago and I believed that the promissory note gave me full title to the property. I want to sell the property, but I am being told that I have to go through the probate process because my mother’s name is still on the property. And that one-third of the value of the property at the time of her death is to be divided between my siblings.
My questions are:
1. Can I collect on the promissory note before any money is distributed at the close of probate?
2. If my siblings take title on the property, can I levy their property and any other assets to satisfy the promissory note?
3. Are there any other options that I can take?
4. Do I have to file a levy against my mother’s one-third share of the property to guarantee that the promissory note will be honored before the distributions of monies at the close of probate?

Is there enough money in the estate to be able to afford to pay off your claim for the promissory note?

You need to get an attorney's assistance on how to file a claim with this estate as an official creditor. I'm sure that someone else who is more familiar with California probate law will provide a more detailed response to your other questions.

No, there is not enough in the one-third share to completely satisfy the promissory note. But I am hoping to recover some of the monies due me. Thanks for your timely response.