As a former Radio Shack employee (thank god for the former) as I am best aware they don't sell component video switches there, only composite.
As far as an amp or switch goes, here is what I would recommend that you go for with your budget in mind
http://cgi.ebay.com/NEW-Pioneer-VSX-...QQcmdZViewItem
This should accomodate all of your present needs as well as allow you some wiggle room for the future. It doesn't have any HDMI switching, but you don't have an HDMI TV. Any receivers that do start at 7-800 dollars currently.