Replacing iPod Screen & Digitizer: Confused?

Hi,

Awhile back I cracked my iPod 4G. It still worked perfectly, though, and it was just a tiny sliver of a crack. I dropped it several times over the following months, however, and it accumulated more cracks. I used to always keep it well protected, and once it's fixed I will NEVER leave it case-less again. Anyways, it got to the point after the second drop that it wasn't worth putting a case on because I knew it had to be replaced soon.

A few nights ago something happened to it, and all I can figure is my Pom Pom chewed it up (Pomeranian). I say this because some glass was missing from the top corner and the frame is slightly bent in that area. My dog is ok though, which is the most important thing. Anyways, if she didn't do it I don't know what happened, but now the iPod refuses to respond to my touch. I can't even unlock it.

I did some research and apparently it's the digitizer. The LCD still works. I need to replace the screen and digitizer, but I hear something about it being difficult and easier just to replace the whole unit (which I don't mind doing). What do they mean by whole unit, though? How do I type that in in order to find the parts I need?

Thanks!