It is not permissible to deal with riba, whether that is by taking or giving a loan. The one who has done that must repent to Allah, may He be exalted, by giving up the sin, regretting it and resolving never to go back to it.
The riba-based loan – despite the fact that it is prohibited and reprehensible – becomes the property of the borrower according to the correct view. So the money that was borrowed belongs to you, and you may make use of it in whatever permissible way you wish, such as buying a car or otherwise.
Please see: al-Manfa‘ah fi’l-Qard by ‘Abdullah ibn Muhammad al-‘Imraani (p. 245-254)
Based on that, it is permissible for you to do Hajj with what you have of that money, so long as you repent from riba, as you mentioned. It does not matter that you are still paying off instalments on the loan.
There is nothing wrong with doing Hajj even if you owe a debt, if the debt is to be paid later on, or is being paid in instalments, and you are able to pay it off on time. Please see the answers to questions no. 3974 and 4241.
We ask Allah to guide us and you.
And Allah knows best.