It looks like to me that you have to attack the queen from a safe square given the threat of Bxc1 with check. The only move I see here is 1.Rc5- the force the black queen down to b3 so that the bishop can be safely taken:

1.Rc5 Qb4 2.Ra5 Kb6 3.Ra4 Qb3 4.Qxb2 and white is up a full rook, and I don't how black continues this attack- it looks completely lost.