WOW! No money for the vet, but you have Internet huh? Maybe since you COMMITTED TO CARING FOR ANOTHER LIVING CREATURE you should FIND the money or give the dog to someone who can care for her PROPERLY.
If there is TRULY no room in your budget for a vet bill (meaning you already live on a diet of Raman noodles and water, have NO credit and can afford only the minimum costs of necessities such as shelter and food and have NOTHING you can sell to raise the money) you have NO RIGHT to have a dog. I think it is FAR more likely you just can't be bothered/ don't want to give up your luxuries and belongings to care for your dog. You make me sick.