We can certainly tell you the answers to those questions -- although it might be best to start at the beginning. No point in putting the cart before the horse.
The HX200V is a still camera that shoots video. If you want to edit the video in Premiere Elements 10, you should shoot only in 1920x1080 AVCHD video -- and then you should make sure that you set up your Premiere Elements project for Full AVCHD 1920x1080. You'll know you've properly set up your project because, when you add your video to your Timeline, there will NOT red lines above the clips on the timeline. It is very important that you set up your project correctly or you will not get good results from the program. (Version 11 sets up your project automatically.)
Has fast is the processor and how much RAM do you have on your Mac? AVCHD takes a lot of horsepower to edit -- so, if you've got a fast Mac Pro or even a powerful iMac, you should be okay. If you're trying to work on a MacBook or an Air, you may have some problems.
I've also created a free 8-part Basic Training tutorial series for Premiere Elements. I highly recommend you check it out before you get too deeply into a project.
Here's the series for versions 9 and 10 of Premiere Elements. They're called "Intro to Premiere Elements".
And, some more links to check
Importing Video http://forums.adobe.com/thread/1065281
-and project settings http://forums.adobe.com/thread/1112086
Saving & Sharing http://forums.adobe.com/thread/1051093
Sharing for Computer http://forums.adobe.com/thread/1058237
AVCHD to DVD http://forums.adobe.com/thread/862611
Elements and AVCHD http://forums.adobe.com/thread/947846
thanks guys. looks like i have some reading to do