She should not be bleeding that long. You should probably have her checked by your Vet and make sure there is no infection. Please consider getting her spay as it is really best fir her overall health.
Does your puppy have pituitary dwarfism or skeletal dwarfism? If she has pituitary dwarfism she will be in perfect proportion with regard to the length of her legs as applied to the size of her body, whereas if she has skeletal dwarfism she will have abnormalities in proportion. In humans it would be comparable to the difference between a midget (perfectly proportioned, just tiny) and a dwarf (normal sized torso but short, stumpy legs and arms and a larger head).
Pituitary dwarves have to content with many abnormalities as they grow. They don't lose their puppy coat, their fur remains soft and woolly like a puppy's coat. They sometimes don't get their adult teeth. They can have hyperpigmentation in the skin, meaning they can have dark patches in their skin for no apparent reason that doesn't correspond to dark hair in the coat. Sometimes they NEVER come into heat, so it's possible that the ongoing heat cycle has to do with the dwarfism since abnormal heat cycles are part and parcel when it comes to dwarfism.
You need to make an appointment to get her into the vet ASAP for an examination and to be spayed. Normally vets like to wait until about 2 months after the heat cycle ends to do a spay because during a heat cycle the blood vessels in and around the uterus are engorged with blood, preparing for her to be bred and carry a litter of puppies. The longer she bleeds without having puppies, however, the greater her chances are that she'll develop pyometra, a life threatening infection of the uterus because as long as she is bleeding, the "door" to the uterus is open, allowing in bacteria that can cause infection. If that happens, the only thing that will save her life is emergency surgery to spay her to remove the uterus. Because of this, the vet may not want to wait to see if she goes out of heat, he or she may want to go ahead and do the surgery anyway just to end the danger of her developing pyometra. If she's in heat it will cost more because there is an increased risk of hemorrhage due to the engorged blood vessels but because of that risk, extra precautions are taken during the surgery. That's the reason for the increased price.
Please don't wait. Most vets are open until noon on Saturday, call in the morning and see if you can get her in there tomorrow (Saturday). If not, call first thing Monday and have her scheduled for the surgery so that you can keep her safe. Please post back and let the forum know what the vet said.