How do you correct bad behaviour on a small dog?

How do you correct bad behaviour that was taught since they were a baby? Ie I got a dog last week she thinks its ok to use my home for a toilet, she jumps up and doesn't have a clue how to walk on a leash (I wasn't aware that she didn't know where to go pee and poo untile we got her from a byb) as for the pee and pooh i have tried EVERYTHING (i let her out every half hour, I walk her, I crate her they (the breeders) taught her to pee on pee paids but she wont poop on it! Im at my wits end I know she is "ajadjustingto her new home but im worried that she has now learnt to pee and poo in the house! I am dedesperateor some ideas as to how to correct these bebehavioursshe is a min pipincherCan older dogs be taught the right behaviour?