At a Solemn Mass, the subdeacon chants the epistle and the deacons chants the gospel. At the much more common Sung and Low Masses, the priest himself does the readings; he chants them at Sung Mass and reads them at Low Mass.
I do not understand what you are asking about minor orders.
By saying that the church “is facing the wrong way,” I assume that you mean the altar faces the people. In most cases, the priest will simply celebrate Mass facing the altar, knowing that there will be a huge space between the altar and the wall at some distance behind it. This is fine, as the point is to face the altar (hopefully this will mean also facing east); the altar does not need to be attached to the wall, though it is much nicer when it is.
If celebrating facing the altar is not possible because the sanctuary steps are immediately in front of the altar, or for some other architectural reason, then a portable altar will need to be set up.