Common theme these days it seems.
I would first measure your tire diameter to find out just exactly what it is though. Most 33's are about 31.5 to 32, so it might be good to know what you have now so you can match it up to the new metric size.
In a 17 these days you might even find one listed directly as being 33x10.50 (if they exist) but the most likely width in metric is going to be either a 255 (almost exactly a typical 10.50) or 265 (wider, but narrower than a typical 12.50).
The aspect ratio is where I'm going to fall flat. My 255/85's are narrow but over 34" tall. A 265/75 is almost every bit a slightly narrow 33x12.50.
So from that experience I'd say that a 255/70 or 255/75 might be the ticket. Here again, IF that tire size exists.
But verify with a tape measure at a tire store!
Paul