Three months is still rather young to acquire bladder control. The puppy may just be too young to be fully housebroken at this time.
Your best bet would be to crate the puppy, as Green Witch suggested. As soon as she is let out of the crate, carry her outside and praise her when she does her business in the right place. I would also keep her confined to the room in which you have the crate--don't let her have the opportunity to pee all over the house, otherwise she will just keep doing it. After some playtime, take her out again, let her do her business outside, then put her back in the crate. By now, you should have some idea of how often she needs to urinate, and try to take her out before she does it in the house. Remember to praise her whenever she goes in the right place.
You can both paper train and housebreak the dog, I've done that with my dogs so I don't have to take them out in really bad weather. You can put some newspaper or Wee Wee Pads in the room with the crate, and place her on them when she is taken out of the crate, if you don't immediately want to take her outside. Wee Wee Pads may work a little better than newspaper because they are supposed to have a scent to attract the dog.
If you don't want to use a crate, the puppy should be confined to the kitchen until she is reliably housebroken. It is also a safer place to leave her when you will be out of the house, or even when you are at home but can't keep an eye on her.
Patience and consistency are the keys in helping your puppy learn where she should urinate and defecate. She is willing to learn, but you have to help her do that by anticipating her needs and restricting where she can go in the house. She will acquire better bladder control as time goes on, and will need to be taken outside less frequently.
Using a crate does make this whole process a lot easier. Confining the puppy to the kitchen is the next best option.
Have your Vet check the puppy for possible urinary tract infections, and ask the Vet about other suggestions for housebreaking.
Nature's Miracle is a great product to keep on hand. It neutralizes odors from urine (which is important in housebreaking) and it helps to prevent urine stains.