Hi From Japan

ok so I will attach some pics.





I wanted opinions on what i can do to to lower this tree into the ground.

About 1 year back i got a peach tree from some one. They were about to toss it. I rescued it and figured after it recovered it`s horrific treatment i would try and make a bonsai of it.
As you can see in attached photos at the base there are roots hanging off it for the first 5cm~.
Originally that was the level it was in the ground.
I am assuming this tree was planted way too deep because the trunk of the tree goes down into the pot and touches the bottom and that is after I cut it down about 8cm. YES! 8cm and at the bottom of the base it is 1.9cm wide.

Now I originally stopped at 8cm because the bulk of the main roots, well most important ones were there.
The tree had only 3 or 4 leaves and over summer and fall it had about 1 dozen leaves. (I actually didn`t think it was going to make it over winter.)
But it did!

I want to get it down about 3cm more by forcing the roots to grow higher up.

What do you think is the best way to do this.

(note that i had dirt piled up all around the base of trunk but the roots did not grow back up there. I cleaned down a week back and it was the same as when i got it those roots are dead)

I was thinking that instead of trying to get them up i could try graft branches lower down, but i have never grafted before sooooooo.

what do you think?
the img does not look so big a gap but there is.