Originally Posted by
WarpedAcorn
You should not be having any issues as Infiltration. I would not recommend Balance though. I tried it and was not impressed.
The biggest thing is, like others have said, is upgrade both your gear and your companion's gear (using Commendations to buy level-appropriate mods is a big boon). Once that is done check to make sure your rotation for your spec is correct (not just spamming buttons, but taking full advantage of procs and intelligently using your CD's). Other things that can help are buying stims (Resolve Stims to boost your Willpower). Another thing is to make sure your companion has all of his abilities clicked for auto-use (sometimes they are not checked off so they won't use them) and is in healing stance.
It might also help to gain a few levels before fighting that boss. Consider doing some Flashpoints, Warzones, and/or Space missions.