My dog bit me hard, what should i do?

ive got a dog from the shelter, a female german shepherd shes about 6 months old and we've only got her for about 2 weeks. really nice to her and all. toys and we give her meat sometiems and treats. has her own fan at night so shes not hot. but she bites us a lot just now i was outside playign w/ her she was in her kiddie pool and i wanted her to come inside but she wouldnt and she kept runnign aroudn not wantign to come in and if i leave her outside shell chew somethign up. so i went and got her and dragged her in by the collar and she bit me a ton of time and im bleeding right now. what should i do with the wound and my dog. and she always gets into fights with strays and other peoples dogs. we almost got attacted by this big dog once. we dont really know much about her history just taht she was a stray and we've been training her but she just wont listen. oh and shes up to date on all her shots.