You can't get these parts new from the dealer today and they might have been unavailable from the dealer back in the time your car was new. After 10 years if they ever were available they aren't anymore. "So sorry" - says Honda. Most other car companies say the same thing. However some brands - like BMW - an owner could get parts for his ride waaay older than 10 years. Ok. Got those interesting facts out of the way.
JC Whitney (like carid) has the body panel which they claim to ship for "free". Junk yard might have somethin' unmolested by rust and damage.
When you say patch I assume you mean sheet metal. When I think of sheet metal, I think TIG welders, grinders, sanders, paintin', sandin', serious body shop level stuff. I haven't seen anybody "go all out" on a Honda civic body the way professionals would do on something like a 50s Chevy. But I'm sure people have done it. I don't work in a body shop so I have no idea. I would look around for a wreck to harvest parts off of. On that note however, I'm noticing fewer places to do this, I see stuff getting recycled much quicker.
