Praise be to Allah.
It is haraam to take riba-based loans, and the one who has done that has to repent to Allaah and regret committing this grave sin. He should hasten to pay off this loan and get rid of riba and its effects. He does not have to pay off anything but the capital; as for the haraam interest, it is not permissible to pay it unless he fears that he may be harmed, in which case he should pay it because he is forced to.
See the answer to question no. 60185.
This woman may go for Hajj using her salary, as her salary is part of her wealth that she owns, and it is permissible if it is in return for permissible work.
If this debt is to be repaid in installments and her travelling for Hajj will affect the payment of these installments, then she does not have to go for Hajj, rather she must start with paying off the debt first, then go for Hajj. If her travelling for Hajj will not affect the payment of these installments, then there is nothing wrong with her going for Hajj, but if it is a supererogatory (naafil) Hajj and she has already performed the obligatory Hajj, then it is better for her to pay off this debt so that she can get rid of this haraam riba.
And Allaah knows best.