why dont you just google how to find them? that's how i completed mine on pearl & platinum
wait. what game are you playing? d/p or platinum?
if it's platinum-
151 is manaphy, and the only way you can get it is by sending it through a shadows of almina (spelling?) game, or getting it by a trade
152 is rotom. go to the forest after 10:00, go to the chateu (spelling again) to the north of the forest, and go to the TV and push A. rotom's in the TV
170 is Glaceon. idk how you haven't seen him yet. i know for a fact a trainer somewhere has it... if i were you i'd either go to hearthome and talk to bebe (if you haven't yet), get an eevee, and evolve into glaceon, or just battle people... look twords snowpoint city first. maybe in the blizzard.
hope i could help