If you Google "Continental Airlines seating chart" you'll get quite a few results. Most are trying to get you to buy your tickets from them, but at least one also has a link to seating charts you can view (depending on which plane's yours).
You might also try going directly to the Continental Airlines web site to find that information (although not all airlines assign seats ahead of time any more). Enter your flight information to check seat availability and advance assignment. If the airline allows advance seating, you should be able to make arrangements at that time.