Essentially the nameserver change has to be made by whichever company you chose to register your domain name with. A quick Google search led to this page on the hostinger forum.
After reading your duplicate post, your question requires clarification - do you want to:
point the domain name, registered with Vautron, to your website hosted on Hostinger, keeping the domain name registered with Vautron
if so then you need to open your Control panel with Vautron - you will need look at Vautron's domain name help faq on how to do this and what information is required, which you may need to get from Hostinger.
Or
change domain registration and point the domain name to your website.