Best way to find out is to go to the T&CO store and ask. I think their prices have changed recently.
I don''t own a Tiffany Novo but I can share the approximate prices my friends paid. One is a 0.9 ct D VVS2 and it was around $20K. Another has a 1.2 ct H VS1 and it was also around $20K. Both of these diamonds were purchased at the end of 2007.
If you look on their website, it shows that a 1ct starts at $9,500 so this would be for the lowest color and carat they carry.
August 2008
1.20 H VVS2 $16,300
1.22 H VS1 $15,500
1.25 H VS1 $17,300
1.25 G VS2 $17,700
1.26 F VS1 $20,700
1.36 G VS2 $19,000
1.40 H VS1 $19,100
1.45 G VS1 $21,700
1.50 G VS2 $25,200
1.56 F VS1 $30,600
Late 2007
0.92 F VVS1 $15,000
1.01 G VS1 $19,500
Looking at these prices reminds me of what a deal I got