Abnormal Lag When Working on an iMovie Project

Hello I have a Mid 2012 MacBook Pro with Retina display, and lately it has this unnormal lag when I'm exporting and working on this 15 minute Grade * graduation video, the fans are always on too, and the computer is hot as California! This computer has had lots of stress this past week as the school year is ending. I had brought this computer into the genius bar before and had passed the graphics card recall program, now there is a extreme lag every once in a while, pretty noticeable when the dock is being magnified.

Plus I Probably need to present it on this computer this upcoming Friday through a projector with HDMI in front of about 500 People, including students. I just hope it will last till that day at least.

Plus its a pain in the neck to bring to the Apple Store, since there never any appointments. Plus the repair time would probably take to long.

The last thing I want is the computer to die just in the middle of the presentation.

Do you think its the 650m Graphics?

My Battery is running at 43 C Lately Approximately.

 

I've brought it in before, back in March, and they say it passed. Plus I won't have the time too. And I'm leaving for vacation soon. I'm worried one day the GPU will just go one day and the recall is over.

Do you guys think they will also cover the screen and hinge if they do do it?

 

Any way to reduce this problem keep it cool????? I gotta present this Friday. And ways to reduce this!!!