It is quite important to create a distinction between domain registration and hosting as this causes confusion to a whole lot of people outside the webdesign world.
Getting a domain name doesn’t mean you have gotten a website but have only registered your website name(domain name).
And you cannot host without having a registered domain. You can both register and host domain
With the same company, or different company but you would have to change the nameserver in your domain registration account(login to your account to do this, or contact the company to help you) to point to your hosting company nameserver.
The nameserver will be provided by your hosting company
Here is the list of website you can register and host your domain in Nigerian(office in Nigeria)
I have personally hosted 30 domains with hostnownow.com and 20 domains with hostsleek.com(with little or no issues)