Where do I get a vinyl sticker of my name made for the windows?
Your closest resource is your local sign shop. These are the places that make all the vinyl for local businesses, either with their logos, or the hours of operation posted in the window, or their name on the sides of their delivery trucks. Your local FedEx / Kinkos can also make these. They should be in two inch Helvetica. A set of driver and codriver names for both sides will probably be somewhere between twenty and forty dollars.
There are a number of reputable online vinyl shops that do specialty work with rally teams in the US. Just to name a few: