Your parents must have a credit or debit card. If not, someone else you know does. On-line is the ONLY way you're going to get these parts. As far as I heard, there's only like 5-7 hobby shops in North America that have decided to sell Redcat. The parts themselves will probably cost less than the s/h, so you may want to put a spur gear and a complete set of front arms on your list. Don't worry, all this stuff won't set you back much. It's better to have it BEFORE you need it, so when you do need it, you won't have to wait.
Oh, when your clutch spring breaks, replace it with a Traxxas one. Mine didn't break after a whole gallon of fuel, but I've heard some go after just a few tanks or less. A replacement HPI heavy duty (hardened steel) clutch bell will help out a lot, as well as a good gear mesh. If you go to the back of your manual or the RCR website you can get the part numbers you need, then order them from topspeedtoys.com or clermontmotorsports.com as ehroof said.
I know this thread was started about your driveshaft, but I'm just giving you a heads up on some issues you will inevitably run into. And to answer your question about this happening to anyone else - yes, it happened to my SV as well. Fortunately my shaft was just sitting on my chassis and the drive cup was still on it! I have NO CLUE how it came off, but it will never happen again, thanks to a few drops of BLUE LOCTITE. If nobody told you or you didn't read it yet, you MUST blue loctite any (EVERY) metal to metal threads, especially the engine mounting screws. Plastic is fine, no need to loctite. Get it at any hardware store, Home Depot, Lowes. Get blue NOT red. Red is permanent, blue is temporary.