dude, u r not gonna get a ho-oh for a heart scale -.-
try to collect some more pokes, or chain shinies, so that people can work a deal out.
No one will give you Ho-Oh OR Lugia for Uxie, Shards, and all those stuff. However, I agree with Hatenko.The best way is to get Colosseum and XD, beat both and transfer the Ho-Oh and Lugia to a GBA game, beat your DS game, and send the via Pal Park because I doubt you'll get any offers this way. Or just buy an action replay.