definitely on the wrong side of the rock>scissors>paper on this one. not alot you can do.
best bet is to focus attack one of the Erebus' and try to knock him out early. you'll have to Tank for the team while Regulus focuses on bursting them down with Mines and MotB. not sure an AA Reg can really get the job done. at the point in the game you got to, with the specs you chose, it might have already been too late.