What worked for my in laws is every time she gets up on you, put your hands firmly on her shoulders, push her into a sitting position, and tell her "no down". If she stays sitting pet her and tell her she is a good girl to reassure her that she is now doing the right thing. The thing is it has to be consistant, everyone has to do the exact samething. If one person is letting her jump on them, it sends the message that she can try it with other people.
Now if something like this didn't work, I have no idea.