that is a low Video Card Speed, but I wouldn't worry about that too much just yet... that's the same video card I had in my imac when I had one, and I did all kinds of editing on it with no problems other than it being a little slow
Mavericks is what you have and is actually my 2 fav OSX, so that is good news haha
I'm hoping you got a white imac honestly, I had a white one and a metal case one and the white plastic one didn't get nearly as hot as the metal one
and Mac peeps will say that is because the metal one acts like a 2nd heat sink to drive heat away from your components, and it does do this somewhat but what I have noticed is that the heat on the metal ones cause the screen to do wild things (like screen burns and discoloration) because of the location of the heat
shame, but if you need any help with the Mac and programs involved hit me up I can usually help
EDIT: grab SMCfancontrol (it is free) if you do get worried about heating