At one week out many breast implant patients will find their implants a little goofy looking. In any case It's important to comunicate with your plastic surgeon as to what your expectations were before the case, and what you think after as well.
There may be very good reasons seen in the O.R. that he did not go as large.
Again ,one week is very early. Implants typically take months to settle into their final position. If after everything is settled, (usually at least 6 mos, sometimes a year or so), then one can have a discusssion as to going back to get larger implants.
Financial arrangements differ from surgeon to surgeon. Remember the surgeon has costs that he cannot control, (i.e.; anesthesia fees, O.R. fees, etc).
Make sure that you are communicating well with your plastic surgeon. Do remember that one week post op is very early...