Replace old flagstones?

[Mattatooi]

I am going to remove big chunk of patio. I am now thinking it might be worthwhile to remove all the flagstones and replace with nicer ones and then I am also thinking of extending it out to the garage side door and do a step down thing all along the edge of it. Just not sure if its possible and would it be easy enough? I am thinking I can use some of the broken up concrete from patio I am to remove to build up the small section and then fill off with new conrcrete. Is this a viable option?

Here is a rough idea as to what I want to do in sketchup. It would be a bit more curvy rather than just an arc. I would also plan to make a step down into grass area garden at the edge all along.




This is what the old patio looks like and the levels;







(I have progressed from these photos and am clearing complete back garden off stones etc and have most of old bush/shrubs gone)


One other issue I am not sure how to resolve is that there is some sort of drainage going on from front of garage;



So just to confirm what I want to do;

1) Remove old patio jutting out and putting grass down
2) Remove all old flags and replace with something new
3) Add new section that is same height as existing patio to allow easy access to Garage side door
4) Add 1-2 Steps down

Is it possible, and if so, how to go about it? And I really not sure what to do with drainage thing?

Thanks