Can content in deleted apps be retrieved?

Question

I was going to transfer some images to my iPad through iTunes. So I selected the photos I wanted and clicked "Apply" (at least I think that's the english translation). I went away from my computer so I don't know what happened, but after I got back the photos were on my iPad, but several apps had been deleted.
The apps are in iTunes under "Applications". I think it must have copied them into iTunes before deleting from the iPad because there are apps in iTunes that I didn't have last time I synced the iPad. I was wondering if the content (like high scores, game saves, documents, images) within the apps are stored there as well? Is there a way to get these back? I've been reading different posts, but I'm a bit confused. English is not my first language, and many people use difficult words or write long answers that just leave me more confused. I tried to find an iTunes usermanual, but just found usermanuals for iPad and iPod.
I've read that if you click "Restore" this will restore your iPad to a point in the past of your choosing. Other people claim it will make it factory fresh. And some people say you get a choice between the two. Some also say that if you click "Revert", it's like an "Undo" button. I don't really understand the difference between "Restore" and "Revert". And what the difference between "Apply" and "Sync" are. Also will "Revert" still work after I've unplugged the device and plugged it back in? Or do you have to click it right away in order to undo?
Some say that the reason apps get deleted is because you sync the device without checking the apps boxes. I don't know if my apps boxes were unchecked, but it seems strange that it would delete apps because of this, and also that there was no warning that popped up.
I've also seen in a post that content from iPad applications can be found in a folder on the computer, but I haven't found any such folder. I found a folder with the actual apps in it though. Are these apps complete with content?
I know if I want the apps back I can just download them again from the app store, but I'm interested in a way that will bring the apps back the way they were, not just redownload.
I read that if you sync again all will be lost, so I want to get it right and not make things worse.
This became a really long post, sorry. Hope people can understand my ramblings and that someone has a good answer.

Answer 1

If you installed a Security Update early this month, about the 2nd or so, and not one since then, run Software Update - if it offers another Security Update, accept and install that one. The original Feb 2012 update had some flaws with regard to MS software in particular; the follow-up update fixed those.