lisa, i don't think you need an app. although phone apps are all the rage now, it isn't for everyone. you should go with a mobile site or a responsive site.
creating an app is a lot of work, even for someone that has a programming or web development background. if you want to create an app for iphone or ipad, first thing you need is a mac and an apple developers license.
if you already have a company site, i would suggest a responsive site. this will cater to both desktop and mobile users. if you already have an existing site, you could create a mobile site.
with a mobile site, later down the road, you can convert it to a phone app using a wrapper like phonegap.