See if you can find parts in El Salvador. They have been importing BMWs at a very good rate for a long time. Also, try to get in touch with these people: http://www.vinesauto.com/
-- They are pretty mcuh a junk yard that carries just about any BMW body panel you may need.
I see that you have found a rear end. Lights and bumper shouldn't be hard to get. www.jlevisw.com
can sell you lights internationally for a good price, I believe.
You can always find sellers that ship internationally on eBay -- just make sure they are reliable.
ohandbytheway, I am from Tegucigalpa, Honduras -- it is nice to see a neighbor on the boards
Bienvenido a United Bimmer