Is there anyway I can get a full pokedex on my HG Rom?

I do not have an action replay. And I really don't wanna buy one. I hope this is the right area to ask this I think it is. ;) So yeah anyway to get full pokedex on my Heart Gold Rom?

You could always trade, but without the Pokewalker, many Sinnoh and Hoenn Pokemon are unobtainable.
GTS is always a good idea if you have wi-fi.

Is the PokeWalker "that" useful for obtaining rare pokemon? But still, we can use GTS.

You can only trade for pokemon in the GTS that you have already seen them... thats my problem and why I need a full pokedex

i would recommend going on the gamefaqs.com forums for hg/ss and talking to people there, you will find a surprising amount of people who are willing to exchange fc's and trade to help you complete your pokedex.hope that helps :)