so you need to buy a bike then? and ebay didn't have any? hmmm...
a bottom bracket shell is part of the bike frame, and you sure can't buy one seperately. im not sure what you are really looking for, but as long as your frame is english threaded, that bottom bracket/crank will fit.
Look at the bottom of your frame where the cranks are supposed to mount up. There should be a threaded tube down there that looks like the picture posted above. That part of the frame is the bottom bracket shell. It is welded to the rest of the frame, it's not a component that you buy. The X-Type crankset that you're looking at comes with 2 bearing cups. One screws in to the left side of that threaded tube and the other screws into the right side. Make sure you get them right b/c if you switch them around, you will mess up the threads. One is right hand thread and the other is reverse thread. Also...measure the width of the "bottom bracket shell" on your frame and use the bearing cup spacers accordingly. Then all you need to do is put the crank/spindle through both bearings and attach the other crank arm.
Oh yeah I almost forgot...you need to "face" the bottom bracket shell so the bearing cups go in perfectly parallel to each other, otherwise you will wear out the bearings prematurely. Don't forget to grease everything up before you put it in.
Basically, if you don't know what you're doing and if this post helped explain...have a shop do it b/c you're probably not ready nor equipped with the facing tools.