An 03? No idea about the prices in your area but it shouldn't be too hard to find a place to plastic weld it for cheap. The price killer will be getting it repainted. Because they can't repaint just that section where the crack occurred they have to repaint the entire piece. So that's the whole tail section. It's probably a lot less trouble to buy a new tail section (You can get them pretty cheap on eBay if you're in the US) but it all depends on price I guess.
The tail section is made from ABS plastic. You can use MEK to glue it back together. Thats what I did to repair some crash damage. Although it is never as strong as the original material. If you want further details just ask.
if you get a 2nd hand section the trick is gettin a colour match to your bike if u cant you will have to respray anyway so its a case of catch 22 do you go for a 2nd hand section and have the possible chance you need to respray it or its not an exact size match and the other you have the section that need repaired its an exact size match just needs fixed and resprayed anyway
me personally i would get the orignal repaired that way you dont have to worry about refitting it you know its gonna fit like a glove