Or you can do the Ultimate Whore Routine which is used amongst the top in the world leaderboards.
Put every single trophy game on gamefly or a rental service. One morning if theres one you don't like and get 15% on them and then post it back the same day so you get another one the day after next. Theres a guy who is like 60th in the world with 8 platinums and 2000 bronze. Thats how he did it. Ridiculous.
On a serious note though, Bioshock is very bronze heavy, until the end of Survivor with no Vita Chambers where you get 2 or 3 golds. I'm playing Unreal now and i have 2 bronze and 2 silvers left. Before i started today i had like 8 bronze. It just shows how heavily bronzed this game is. The campaign isnt but with all the weapon trophies etc. it mounts up.
Edit: First post of page 666. Gulp :(