There are a few myths about mobile devices that you will need to address in regards to your website:
Myth 1. You need a separate website for mobile. While there are certain settings that can be turned off for mobile, the advent of responsive web pages has pretty much made the .mobi pages obsolete. You do not need a mobile version of something that works fine on its own, so don't let some late-to-the-party web developer try to sell you a separate mobile page.
Myth 2. You need an app. Please don't pay someone to develop an app for you unless you have an idea for a useful component people might want on their devices. If you are looking to add specific functionality, then it might make sense, but if you want to get customers to buy something from you, an app will not really help. Most devices are perfectly capable of navigating good responsive websites in order to do anything someone with a desktop would do on the site. If you don't need a special program to install on someone's desktop, you also don't need an app.
Myth 3. My old website is just fine the way it is. Google has said mobile-ready websites will benefit in searches. 50% or more of new devices are mobile devices. Some of these are oversized and will see your site just fine, but others won't render your menu or see your entire page. If your images are in pixels instead of percentages and you've got a fixed-width webpage (even a really skinny one), you need a change.
Myth 4. I'll just use social media instead. Just remember that the social media venue you choose owns your content and your customers when you make this choice. Yes, it's frustrating that your two year-old site is worthless, but it's still yours. Using social media is like hiring a clown for a birthday party. People might have fun and it might go over fairly well, but it's slightly tacky, and no one will take you seriously if you do it year after year. You need the clown, but it's there to send customers to your real website, and your real website needs to look better than the clown site.
I was once told that owning a car should cost you a few thousand dollars a year over its life. People kind of expect it with cars, but they don't really think about it. The problem is that you need washes, oil changes, new mufflers, new tires, and even that original purchase price. Many people like to think websites are somehow immune to the costs of ownership happily assumed with automobiles or computers. While you might not need a totally new website every year, you do need to keep it updated (content and software). And yes, you really do need a new one once in a while, and, just like that old Chevy Cavalier, nobody really wants your old version, so all the money you put into it was an investment to keep IT going at the time, not in what you now need.
The need today is to have a website that works right now. Passive Ninja can help.