How do i stop my dog from peeing in the house ?! PLEASE MY MOM MOGHT GET RID OF HER IF SHE DOESNT STOP :(?

Okay, so we got my dog 6 months ago & we got her at the age of three because the people who had her had to give her up because they were getting to old for the dog. Anyways! When we got her she peed on the floor but she got used to the house and scratched at the door when she needed to go out and we let her out. Then all of a sudden about a month ago she just peed wherever she wanted to & whenever she did , we showed her the pee and hit her on the nose (not hard). We checked her out for a urinary tractinfection. & they gave us all that we needecd to medicate her with and it helped aalot until a couple weeks later .. she will pee all over the place now ; wherever she wants !! now we keep showing her the pee and hitting her (not hard) on the nose & we lock her up. PLEASE HELP for suggestionss !!!!!!