Just selecting a new toilet can be challenging, but the tile make it more so. Let's start with the toilet. If you will go to the top of this page and click on "Toilet Reviews". Now select "Shopping" followed by "Toto Toilets". Now you can peruse all of the many Toto models. Now comes the floor. It is unlikely that you can find a new toilet of any brand that will fit into the space the old Norris comes out of, and matching tile colors exactly can be difficult to impossible, and "almost matches looks like *&%$. When you can't match colors, then go with contrasting color that can actually enhance the appearance. For example, if the original tile is cream colored, get some light blue to fill the space. I would suggest you consider replacing the flange and tiling all of the space so the new flange will rest on top of the new tile. That's where it is supposed to be, but almost certainly in your case the tile was done as a remodel so the flange is too low.