I assume your asking because you don't have unlimited wads of cash lying around you, my only suggestion would be hiring a caregiver that is not associated with a service, cutting out the middle man. The state can help fund these services however, and a visit to her doctor to discuss her limitations and how best they can assist you in increasing her benefits if she has any would help you get the answers you need.
My family created a schedule and with the help of neighbors we all took turns going everyday until the problem required full time home health care. You may be surprised to learn she has neighbors who could use a few extra dollars or even a college student who needs extra change.
Good luck and bless