External monitor slowing Internet connection?

I recently purchased a 21.5" Samsung monitor that is connected to my late 2009 13" 2.26GHz 8GB RAM MacBook Pro through a VGA connection with the VGA to Mini DisplayPort adaptor. Since I've started using it, my Internet connection has slowed to a crawl. I've researched the issue online and external monitors can apparently created wireless interference. I'm using a 2011 AirPort Extreme 802.11n/b/g. Is there anything I can do to eliminate this interference?