The description of support services (including frequency and group size) should be indicated on your daughter's I.E.P. If you feel that the services recommended are not appropriate to her needs, you can request an impartial hearing to review her case. An extremely helpful guide to obtaining appropriate services for your child is attorney Lawrence M. Siegel's book, The Complete IEP Guide: How to Advocate for Your Special Ed Child.
As a parent, you can ask for any number of modifications/accommodations in your child's program that can be written right on the I.E.P. If she's not making progress under current conditions, ask for her case to be reopened and request the changes you feel are necessary. Knowing your rights and how to apply them will make you the strongest advocate for your child.