There are many hosting providers who provide support for sever side scripting, the problem is deciding which type of scripting you need, Java, PHP, ASP.
If you want to try using your current hosting see this article - the only problem with using browser side detection is that you will need to keep the script up to date as new browsers are released/used on mobile devices - this is the messy part I mentioned before.
For server side detection there are many ways of doing this with varying degrees of complexity eg using PHP see this example
Before attempting server side scripting I would advise acquiring some programming basics, gaining further knowledge on FTP - there are many online tutorials - and look at hosting providers in detail - some provide this as as part of the package - for mobile browser detection and redirection.