I have a 1st gen MBA and just added a 22" external monitor capable of 1920 x 1080. But there's a giant black stripe around the image on all sides, and I am really only using about 2/3 of the monitor. Does anyone know how (or if) I can make this image larger? I'm using the VGA cable but I could use the DVI. What would help? The video card in the MBA is GMA x3100. THANKS!!