Iv done alot of outdoor work, Im currently trying to make a living running a land scape company.
I have the experience to back up what Im saying.
You are screwed !
Ok not really, you have 2 choices.
add the cement and tile over it, or you can dig down around it, put in about 2" of sand for a base, then use pavers, interlocking ones look best I think. Or bricks, and create the extension out of that.
Tile is good heavy adn strong when it has proper backing. You cant use it on dirt though, dirt moves, sinks, gets soggy and mushy, and allows air to get in and under. Tile is easy to break stepping on it in dirt, you can never dig it down enough to stop its slopping around and becoming fragile.
I know some people who have it outside in dirt, its unusuable space. They put a frame of 2x4s, sand, then the tile and it works pretty well, for setting some permenant pots on. You cant walk on it or use chairs or anything to make it a usuable space.
Iv done lots of landscaping, and set alot of tile. Your going to have to do it right and use the sand/pavers, or cement then tile.
Sorry to dash doing it on the cheap and easy, but if you did, you wuold have broken, muddy, ugly tile in a short time and it would all be wasted.

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