Try your LHS first. Then you don't have to pay shipping. If they can't get it go to the HPI site, Tower Hobbies or A Main hobbies. I think your looking for the 'underhead', part #1447. (Double check with your manual. I just realized that one is for the 4.6) If you don't have the manual, you can probably find it on the Team FastEddy site. There are links to it on the main forum page.
You have obviously cross threaded it. Try removing it and re-installing it carefully. If you didn't jam it in too far the last time, it's possible to get it threaded in correctly.
You're FAST, HeartBreak............:jet: