I would suggest using a recipe builder site to put in the ingredients and figure out the info. There's really no way of telling how much of any one pizza slice is due to crust, toppings, etc. Crusts are different thicknesses and unless you have a weight, you don't know if what yours is and how it matches up to a website total.
Pizza has a huge variation. I've gotten to the point where I either order from a place that posts their calories (and go by weight of slice) or, more frequently, make it at home, and I've loaded all the ingredients into a recipe builder.
"If you drop an egg, you don't say, 'Oh, shoot' and drop the other 11, do you?"
-Source unknown, but obviously brilliant
Reached goal 4/16/2010...but kind of afraid to look these days