There are 7 new Trophies in this DLC.

Bronze

Brutal Footsteps
With Silent Footsteps skill active, Brutal Melee an enemy player

Silver

Demolotionist
Demolish both buildings by winning Search & Destroy as ISA and Helghast in Salamun Market.

Tactical Master
Be playing at the moment your faction secures all four Tactical Spawn areas simultaneously in Salamun Market.

Death by Proxies
Using Proximity Mines, kill two enemies within one minute in Blood Gracth

Blood Streak
Get 5 Kill Streak in Blood Gracth

Little Big Weapons
Get 15 kills using secondary weapons in a single match

Automata for the People
Destroy an enemy Sentry Turret, Sentry Drone, and Medi-Droid in the same round

http://www.ps3trophies.com/forums/trophy-news/55520-killzone-3-retro-map-pack-dlc-trophy-list.html