Many people who adopt dogs change their names. I think it's ok, especially seeing as she doesn't answer to her current one.
As for the rest, it sounds like she needs a lot of training. I would start with the basic just like with a puppy. Sit, stay, come here and teaching her her name. With yummy training treats like boiled chicken pieces or cheese. A training class could help too, but I agree with the advice above, there are so many great videos online about training.
When you say she's horrible on the leash, do you mean that she pulls? I find the best way for that is to stop and stand still until the dog calms down. Then praise and give a treat. Restart walking and ask her to 'heel'. If she walks nicely, praise and give a treat. As soon as she pulls again, stop ad restart the same process. It's frustrating, but eventually they get bored of stopping and learn. lol This works for other leash issues like refusing to walk to too.