All right thank you for the suggestions everyone... Yeah I think I can actually download the DLC on PC as compared to the 360.
Not sure what you mean by DLC, since Morrowind doesn't have any.
If you mean the two expansions, they cannot be downloaded anywhere. But GoTY comes with them.
If you mean the Official Plug-ins, yes they are for PC only, and can still be found at the Official Bethesda site. Or fixed versions can be found on the mod sites.
Where would you recommend buying the GOTY edition at?
Steam would be the easiest.
But you can also try Ebay, or other sites that sell PC games.