I agree with the other posts about using the moist wipes - we all use them and they are great, although the child needs to be able to use toilet paper in places where wipes aren't available (school, public rest rooms).
With my son, it worked to establish "big boy" responsibilities and privileges. If he couldn't put away his Legos, he was still to young to play with them. If he couldn't eat a variety of foods in restaurants, he couldn't go to Disney World. If he couldn't wipe himself, he was too little to play outside by himself. Use whatever "currency" has value to your child. If she's too little to wipe herself, she is too little to watch certain TV shows or have certain toys, whatever works.
Good luck and stay consistent! This will pass when she gets to school! And she will NOT like the younger child getting privileges for responsible potty habits, if she is still whining on the toilet!