Try to increase traffic to it by providing the right type of content. It's hard to give you any more specific advice since no extra info is offered on the type of site you are running, however rankings are usually based on traffic. More and more people will visit your website and use it and / or purchase product and / service from it if it has value to them or offers something different from what is already available.
The last resort for you could be to go on sites like Fiverr and buy traffic and subscribers (again, don't know if this applies to your case). Either way, if your rank is that low now a lot of work lies ahead if you want to make it to 25K.... Good luck!
He basically needs SEO optimization. If you guys don't how to do, just make a quick search on google.