Sounds like you need a VGA to HDMI converter, here is a link to a bunch of them. Some caveats, so read carefully
vga to hdmi converter - Google Search
Tech Note for 720p HDTV: The only laptop or computer resolution setting that is compatible between the 90-12014 and 720p HDTV is 1280 x 720 @ 60Hz. Make sure your computer or laptop has that resolution setting before purchasing this unit. Also make sure in the graphics media driver settings of your computer that both the computer AND remote monitor has the refresh rate set to 60Hz.