What bonuses are gotten from Mass Effect: Infiltrator?
There are no weapon unlocks for Mass Effect 3, that was misinformation. All you can earn for Mass Effect 3 are War Assets for completing Infiltrator and points toward your Galactic Readiness rating by uploading Cerberus intel.
Source: Video interview with Mass Effect Infiltrator design director Jarrad Trudgen. Relevant information at 3:04.