As crittersitter said, just stop allowing her to take advantage of you! You are the human and she is the dog, make the dog adapt to you, not the other way around! She'll love you for the guidance really!
Since you've had her with you such a short time, I'd suggest slowing things down, give her more time to learn about you and the new household and your rules before taking her out to any dog park or other outside venue. You both need time to learn each other and to form a bond, learn how to communicate with her, learn what makes her happy and what makes her tense, what she knows well and what needs some work. All dogs are different, but for any and all of them learning about who they are, and allowing them to learn who you are, takes time...give her that time!
As I said before, don't be bashful in the meantime letting her know YOUR RULES! Dogs really tend to appreciate clear boundaries and or rules. Don't, whatever you do, fall into the awww poor puppy has had such a rough time school of thought, it's never helpful even if it's true...set clear boundaries, enforce them calmly, but insistently, and it'll all work out as well as it can....often much better than you can or will have ever hoped! Good luck! Please keep us posted on you're progess!
It's not the size of the dog in the fight, it's the size of the fight in the dog. Mark Twain